23 October 2025, Volume 38 Issue 5
    

  • Select all
    |
  • Development and Challenges of Surface Planarization Technology for Single Crystalline Diamond
    YANG Kuo, CHAI Zhimin, DAI Yuanjing, LIU Yuhong, LU Xinchun
    China Surface Engineering. 2025, 38(5): 1-33. https://doi.org/10.11933/j.issn.1007-9289.20250415001
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    Single-crystal diamond (SCD), owing to its exceptional physical properties—including an ultrawide bandgap of 5.5 eV, an extremely high breakdown electric field of 9.9 MV / cm, and an outstanding thermal conductivity of 22 W / (cm·K)—is widely recognized as a revolutionary material capable of overcoming the performance limitations of silicon-based integrated circuits (ICs). However, the extraordinary hardness (Mohs hardness of 10) and extreme chemical inertness of diamonds present significant challenges for achieving atomic-level surface polishing, which is crucial for their application in high-end chip manufacturing. This study focuses on the development of atomic-level polishing techniques for SCD, systematically reviews the evolution of polishing technologies from micro / nanoscale to atomic precision, and identifies key breakthroughs to overcome existing machining limitations. Additionally, this study examines the characteristics and applicability of various polishing methods, thus providing valuable insights for practical implementation. First a mechanical polishing techniques, including conventional and ultrasonic-assisted methods, are investigated comprehensively. Whereas these approaches offer straightforward processes, the inherent “hard-on-hard” friction inevitably introduces surface defects, thus rendering it difficult to achieve subnanometer surface smoothness. Subsequently, high-energy beam polishing technologies, such as lasers, ion beams, and plasma polishing, are examined. Although these methods replace abrasive particles with high-energy particles, issues such as inferior selectivity, deep thermally affected zones, and particle implantation limit their ability to achieve low subsurface damage and subnanometer planarization. The third category, i.e., multifield coupled polishing, which includes chemical-mechanical polishing and plasma-assisted polishing, leverages synergistic effects for surface planarization. However, these methods are characterized by complex processes and low polishing rates. Based on a detailed comparative analysis, this study highlights the significant challenges in satisfying the stringent requirements of IC manufacturing: subnanometer precision, minimal damage, and high processing rates. The findings suggest that, although existing polishing techniques are adopted in specific applications, they remain inadequate for completely satisfying the abovementioned demanding criteria. Achieving atomic-level surface polishing requires not only gradual process improvements but also systematic innovations in theoretical understanding and process development. This study emphasizes the necessity of cross-scale control from macroscopic process parameters to microscopic atomic behavior to precisely regulate material removal mechanisms, including the synergy between mechanical shear and chemical etching, as well as the energy threshold for atomic bond breaking. At the fundamental research level, the development of atomic-resolution in-situ characterization techniques and first-principles computational models is crucial for establishing quantitative relationships between process parameters and atomic surface configurations. The results indicate that atomic-scale manufacturing must rely on multifield synergistic regulation combined with in-situ atomic-level monitoring and intelligent control to achieve precise process optimization and further advance ultraprecision manufacturing. Despite significant progress, several technical bottlenecks remain in achieving atomic-level polishing for SCD. First, multifield coupling mechanisms are yet to be fully understood, thus resulting in trade-offs between the material-removal rate and surface quality in mechanical polishing, as well as issues such as high equipment costs and instability in energy-beam polishing. Additionally, multifield coupling techniques present challenges such as dynamic parameter mismatches (e.g., pH fluctuations and uneven light distributions), thus hindering stable and efficient processing. Second, intelligent control systems for polishing processes remain underdeveloped, with limited real-time optimization capabilities and insufficient integration of smart algorithms with in-situ characterization techniques. This results in a trial-and-error approach for process optimization. Third, the industrialization of green and efficient processes is hampered by key obstacles such as high energy consumption, environmental risks, and low process repeatability, which pose significant constraints for large-scale applications. Hence, future research should focus on three key directions: (1) deepening the understanding of multifield coupling mechanisms, including the interactions between mechanical forces, chemical etching, and energy fields (e.g., light, sound, and plasma), and establishing quantitative models of parameter synergy; (2) advancing intelligent control technologies, such as machine learning-based algorithms for real-time process optimization, and developing high-precision multifield coupling equipment to enhance process stability and consistency; and (3) promoting green and efficient processes, including the development of environmentally friendly chemical systems and energy-saving machining methods, as well as establishing standardized protocols for industrial implementation. The key innovation of this study is its systematic evaluation of polishing technologies and the identification of critical research directions to overcome diamond-machining challenges. By comprehensively assessing the strengths and limitations of existing methods, this study provides a solid foundation for the development of next-generation diamond-based ICs as well as offers valuable insights for academic researchers and industry professionals in advanced semiconductor manufacturing.
  • Research Progress in Abrasive Technology for the Chemical Mechanical Polishing of Chips
    MA Jiahui, CHENG Jie, CHEN Jinchi, JIAN Leizhu
    China Surface Engineering. 2025, 38(5): 34-59. https://doi.org/10.11933/j.issn.1007-9289.20241016001
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    As the cornerstone of the digital economy, chips are advancing toward integration, low power consumption, intelligence, and functionality. Chemical-mechanical polishing (CMP) has become a critical technology for achieving ultrasmooth and defect-free global and local planarization in chip manufacturing. The abrasives in polishing slurry act as a “bridge” to facilitate the synergistic mechanical and chemical processes that are essential for high-precision material removal. Moreover, abrasives play crucial roles in achieving efficient, atomic-level, and smooth manufacturing of various materials, and they have become focal points of CMP research. Over the past few years, extensive efforts have been devoted to developing high-performance abrasives for chip manufacturing. In addition to being integral to the mechanical aspects of CMP, where they perform the physical removal of materials, abrasives also contribute chemically by interacting with the materials being polished. Hence, CMP performance is significantly influenced by the properties of the abrasives, including their dispersion stability, mechanical properties, morphology, particle size, and chemical reactivity. Maintaining the dispersion stability of abrasives is vital for prolonging the shelf lives of polishing slurries and minimizing defects, such as scratches. Furthermore, precise control over the morphology and size distribution of the abrasives can significantly reduce scratches on polished surfaces. Chemically reactive abrasives enable efficient material removal, which improves the overall polishing rate and surface quality. The research progress on typical abrasives used in CMP for semiconductor manufacturing is reviewed, with a focus on materials such as SiO2, Al2O3, CeO2, and diamond. SiO2 abrasives are especially renowned for their abilities to satisfy the ultra-high-precision surface quality requirements of advanced semiconductor devices as well as their versatility across a wide range of materials and processing conditions. SiO2 abrasives are essential for the manufacturing of modern electronics, particularly for applications that require exceptionally smooth and defect-free surfaces. Al2O3 abrasives are widely used in the CMP of substrates such as SiC, GaN, and sapphire, and they contribute to a favorable balance between performance and cost. CeO2 abrasives are highly effective for achieving efficient material removal and fine surface finishes owing to their unique combination of mechanical hardness and chemical reactivity, which makes them ideal for specialized CMP applications. Diamond abrasives are essential for planarizing ultra-hard materials, including diamonds and other hard substrates, for which conventional abrasives are ineffective. In addition to these conventional abrasives, there is growing interest in novel abrasives and the integration of energy-field-assisted polishing techniques. These techniques utilize external energy fields (such as electric, magnetic, or optical fields) to enhance the physical and chemical interactions between abrasives and substrates, thus helping overcome the limitations of conventional abrasives when working with hard or chemically inert materials by providing an additional energy input. Moreover, there is ongoing research on the behavior of abrasives at the nanoscale, as semiconductor manufacturing is advancing toward smaller and more complex devices. Advanced characterization techniques and computational simulations were also used to gain a deeper understanding of the CMP process at the nanoscale, with the aim of understanding the atomic-level interactions between abrasives and substrates. Improving the precision and efficiency of the CMP processes is crucial, particularly for the production of next-generation semiconductor devices. Additionally, a forward-looking outlook on the application of abrasives in chip CMP is provided, and the needs for continued process optimization and the development of novel abrasives are emphasized. Furthermore, the theoretical mechanisms that govern CMP behavior must continue to be explored, as this will provide a strong foundation for future innovation in the field. This study aims to provide valuable insights and theoretical support to guide future research and development in CMP for the purpose of ultimately driving advancements in semiconductor manufacturing technology.
  • State-of-the-art and Prospectives of Atomic-level Grinding Technology for Semiconductor Substrates Used in High-end Chips
    WANG Haoxiang, KANG Renke, LI Shengbo, DONG Zhigang, GAO Shang
    China Surface Engineering. 2025, 38(5): 60-82. https://doi.org/10.11933/j.issn.1007-9289.20250609001
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    As the dimensional scaling and functional integration of high-end semiconductor devices accelerate, ultra-precision finishing of substrates such as monocrystalline Si, SiC, AlN, Ga2O3, and GaN is now constrained by atomic-level accuracy targets; while this context motivates the field, the present review concentrates on what enables—and limits—atomic-level grinding (ALG) as a deterministic route for planarization and thinning of semiconductor wafers, synthesizing mechanism-level knowledge with process engineering practice to clarify how ALG governs surface integrity, subsurface damage (SSD), total thickness variation (TTV), and mid-spatial-frequency (MSF) errors that ultimately control device yield and performance. We first dissect material-removal mechanisms from the atomic to the mesoscale and explain how ductile-regime grinding can be stabilized by connecting lattice bonding, elastic-plastic anisotropy, fracture resistance, and tribochemistry with the thermomechanical fields at the tool-work interface: for Si, pressure-induced phase transformation and subsequent tribo-oxidation support ultra-smooth shearing of a metastable / altered layer; for SiC, amorphization under high contact stress combined with oxidation-assisted weakening suppresses brittle fracture and enables Å-level topographies; for III-N and ultra-wide-bandgap oxides (GaN, AlN, Ga2O3), defect-mediated shear coupled with chemistry- or field-assisted bond weakening—via alkaline or oxidative chemistries and hydration reactions—reduces the effective activation energy for interfacial slip. Across materials, we highlight controlling nondimensional groups, particularly the ratio of undeformed chip thickness to the critical depth for ductile removal, that demarcate transitions among brittle chipping, quasi-ductile ploughing, and true ductile cutting, yielding mechanism maps that relate abrasive size and morphology, contact pressure, temperature, and chemistry to SSD depth, residual stress, and roughness. Building on these mechanisms, we catalog processing strategies and system-integration choices that operationalize ALG at wafer scale: fixed-abrasive ultra-fine diamond grinding with electrolytic inprocess dressing (ELID), ultrasonic-vibration-assisted modes that lower effective cutting forces, and laser / thermal assistance that locally softens the surface to tip the balance toward plasticity; chemo-mechanical synergy using oxidants, complexants, and pH / redox control to form and continuously renew a weak interfacial layer that can be sheared at nanometric depths of cut; and co-design of tooling and kinematics—resin / metal / ceramic bonds, abrasive size distributions, wheel-topography conditioning, and path planning (spiral / raster with dwell control)—to suppress TTV and MSF on 200-300 mm wafers. We summarize robust process windows from successful reports—high wheel speed, low feed and depth to keep the undeformed chip thickness sub-critical, ultra-stiff low-runout spindles, temperature-stabilized machine / wafer stacks, and low-noise workholding to prevent chatter—while analyzing fluid chemistry as a lever that intersects with frictional heating and contact time to regulate altered-layer thickness and face-dependent removal selectivity. Metrology and control are treated as first-class topics: in-situ force / acoustic- emission / temperature sensing for contact-state identification; optical interferometry for shape and MSF; and XPS / TEM / Raman for altered-layer chemistry and SSD, all feeding model-based and data-driven control frameworks that span multiscale simulation (DFT / MD to continuum) for predicting critical depths and stress fields, physics-informed machine learning for tuning parameters to minimize SSD at target MRR, and digital twins that couple thermal-structural drift, wheel-wear evolution, and wafer geometry for adaptive compensation of TTV and edge roll-off. From this synthesis, we make explicit the principal challenges: robust suppression of brittle events on hard, chemically inert wafers without sacrificing throughput; quantitative control of SSD at tens of nanometers or less with verifiable, crystallographic-face-dependent selectivity; wafer-scale flatness and TTV control during thinning, including edge roll-off mitigation; MSF management induced by periodic wheel topography or path artifacts; tool wear, self-sharpening, and wheel-state observability; thermal and dynamic stability of large, low-stiffness wafer stacks; seamless integration with downstream CMP without re-introducing defects; and greener chemistries that maintain mechanochemical efficacy. Finally, we identify emerging directions likely to be most impactful: hybrid energy fields (ultrasonic / laser / plasma-assisted ALG) to expand the ductile window; closed-loop, sensor-rich control with real-time detection of critical-depth excursions; physics-guided AI for multi-objective optimization of roughness / SSD / MRR subject to throughput and sustainability constraints; micro- / nano-textured abrasive tools that engineer contact states and chip evacuation; and standardized protocols plus open datasets for cross-material benchmarking. Collectively, the review delivers mechanism maps, process-integration guidelines, and a research agenda aimed at deterministic attainment of sub-nanometer roughness and minimal SSD in semiconductor substrate grinding, offering theoretical insights and technical references to guide future advancements in atomic-level grinding for semiconductor manufacturing.
  • Advances in Chemical Mechanical Polishing Endpoint Detection Technology for Integrated Circuits Manufacturing
    ZHAO Guangen, WANG Chengxin, CHEN Jianxiong, HUANG Yuhua, HUANG Ruochen
    China Surface Engineering. 2025, 38(5): 83-98. https://doi.org/10.11933/j.issn.1007-9289.20241202001
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    Chemical mechanical polishing (CMP) is a pivotal process in advanced semiconductor manufacturing that enables wafer surface planarization. CMP endpoint detection (EPD) technology achieves precise control over the wafer surface topography and material removal rates by dynamically adjusting the polishing pressure in different zones through real-time measurements of the thin film thickness. However, current EPD techniques face challenges in accurately capturing material removal rate variations in localized regions of wafers with complex patterns and nonuniform density distributions, leading to discrepancies between the detection signals and actual polishing states. Moreover, polishing processes involving multi-material systems suffer from limited signal resolution and selectivity, making it difficult to precisely detect interface changes. Thus, the investigation and optimization of CMP EPD technologies are crucial for addressing the challenges posed by multi-material and novel structures and improving the precision and stability of the process. This paper systematically reviews the current research on CMP EPD technologies, focusing on the principles, characteristics, and advancements in offline (e.g., the time method) and online (e.g., friction-based, optical, and eddy-current techniques) detection methods. In the early or stable stages of the CMP processes, endpoint control relies predominantly on experience and time-based polishing and lacks precise online detection. With technological advancements, four-probe offline detection instruments have been employed for post-polishing evaluations. However, these methods require extensive data accumulation and an understanding of the process parameters to determine the optimal polishing time for each material and process. Advanced CMP processes involve diverse materials, such as shallow trench isolation, interlayer dielectrics (SiO2), metal interconnects (Cu), and barrier layers (Ti / TiN), each with distinct polishing rates and removal mechanisms. Offline detection methods struggle to adapt to these variations in real-time. In addition, time-based offline detection fails to account for wafer-to-wafer differences, rendering it insufficient to meet the demands of advanced CMP processes for real-time monitoring and rapid response. Consequently, online detection methods are often required to ensure process stability and product quality. Online EPD technologies enable real-time monitoring and analysis of polishing conditions during the CMP process, ensuring the achievement of the desired endpoints. These technologies are pivotal for automating the polishing process and enhancing the integrated circuit yield. Friction-based online EPD techniques offer strong real-time performance and ease of integration, making them particularly suitable for capturing dynamic mechanical interactions during polishing. However, these methods are significantly influenced by process conditions, such as pad wear and slurry flow, with signal noise and external disturbances undermining the detection accuracy and reliability. Future advancements in friction-based EPD should include the introduction of adaptive calibration mechanisms to mitigate external disturbances and the development of high-sensitivity friction sensors to explore the nanoscale film removal characteristics and meet the requirements of advanced process nodes. Optical EPD techniques typically achieve sub-nanometer resolutions for film thickness measurements. However, optical methods are highly sensitive to environmental conditions, with polishing slurry, debris, and surface contamination potentially interfering with signals and reducing detection precision. Future improvements in optical EPD systems should focus on enhancing the optical system design to resist interference from slurry, contaminants, and environmental fluctuations. Eddy-current EPD provides nanometer-level thickness measurements at a relatively low cost and can be easily integrated with CMP equipment. However, its insensitivity to insulating materials, such as dielectric layers, limits its ability to independently detect dielectric and nonmetallic films. Furthermore, the development of eddy-current sensors capable of achieving high-precision (nano- / sub-nanometer scale) measurements under large lift-off variations remains critical for future research. In the future, multi-physics field fusion methods will play a pivotal role in enhancing the detection performance to address the challenges posed by multilayer film stacks and heterogeneous material systems in 3D devices for advanced process nodes. By integrating optical, eddy-current, and friction-based techniques with multi-sensor collaborative acquisition and data fusion algorithms, the selectivity and accuracy of EPD can be significantly improved. Furthermore, AI-driven intelligent signal processing equipped with robust feature learning, pattern recognition, and intelligent decision-making capabilities enables the analysis and prediction of complex three-dimensional structural signals while adaptively adjusting the parameters, thereby enhancing the adaptability of EPD technologies. Additionally, flexible and customizable sensor designs combined with micro-area detection techniques contribute to increased spatiotemporal resolution, facilitating the precise monitoring and dynamic regulation of localized polishing conditions.
  • Research on Tribochemical Mechanism in Chemical Mechanical Polishing of GaAs
    GAO Jian, REN Xingyun, LIANG Dexu, ZHANG Honglin, ZHOU Huaicheng, JIANG Liang, YU Bingjun, QIAN Linmao
    China Surface Engineering. 2025, 38(5): 99-106. https://doi.org/10.11933/j.issn.1007-9289.20241229001
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    Nanoprecision surface manufacturing technology has important applications in many high-tech fields, such as semiconductor photovoltaic and integrated circuit manufacturing. Chemical mechanical polishing (CMP), the most critical technology in ultraprecision surface manufacturing, guarantees and promotes the application and development of high-end technologies. Gallium arsenide (GaAs) is the most important second-generation semiconductor substrate, and it is widely used in microelectronics and optoelectronics. High-quality GaAs substrates require the absence of surface / subsurface damage, preservation of lattice integrity, and sub-nanometer level surface roughness. CMP is currently the most effective technology to achieve these requirements. As material removal in CMP is predominantly governed by tribochemical reactions, understanding these mechanisms is essential for enhancing the surface quality. In this study, the tribochemical removal mechanisms during CMP of GaAs were investigated by conducting nano-wear experiments using an atomic force microscope (AFM) equipped with a silicon dioxide (SiO2) microsphere tip under acidic (pH ≈ 4), neutral (pH ≈ 7), and alkaline (pH ≈ 10) conditions. Material-removal regions were characterized using high-resolution transmission electron microscopy (TEM). Density functional theory (DFT) calculations were employed to elucidate the atomic removal mechanisms. The results indicate that material removal on the GaAs surface is the most severe in alkaline conditions, with removal depths and volumes being significantly higher compared with those in neutral and acidic conditions. Specifically, the material removal depths in the acidic, neutral, and alkaline conditions were approximately 9.4, 19.2, and 24.2 nm, respectively. Similarly, the material removal volume increased from 4.99×106 nm3 in acidic conditions to 8.84×106 nm3 in alkaline conditions. A TEM analysis revealed that the lattice structure in the material-removal regions remained intact, suggesting that tribochemical reactions dominated the removal process without causing significant damage to the underlying atomic structure. The significant change in the charge density at the GaAs / SiO2 interface, as calculated by DFT, suggests the formation of Si-O-Ga bonds. Furthermore, interfacial charge transfer was the most pronounced in alkaline conditions, where OH- ions promoted the formation of Si-O-Ga bond bridges and weakened Ga-As bonds, facilitating material removal. The calculations showed that the charge transfers in the subsurface region of GaAs were 0.032, 0.039, and 0.042 e / Å3 under acidic, neutral, and alkaline conditions, respectively. This increased charge transfer in alkaline conditions leads to a more significant weakening of the Ga-As bonds, making the material more susceptible to removal. Additionally, CMP experiments conducted under the same pH conditions confirmed that the surface roughness and material removal rate (MRR) were optimal in alkaline conditions. The surface roughness (Sa) values were approximately 3.61, 1.87, and 0.81 nm for acidic, neutral, and alkaline conditions, respectively. The MRR values followed a similar trend, with the highest rate observed in alkaline solutions (22.6 nm / min), compared with those in neutral (19.4 nm / min) and acidic (13.2 nm / min) conditions. This consistency between the nanowear experiments and CMP results underscores the importance of pH in controlling the tribochemical removal process. These findings suggest that the presence of OH- ions in alkaline conditions enhances the formation of Si-O-Ga bonds and increases charge transfer at the GaAs / SiO₂ interface, leading to more efficient material removal. This study provides valuable insights into the pH-dependent tribochemical removal mechanisms during the CMP of GaAs, providing a foundation for optimizing CMP processes for other binary materials. The integration of single-abrasive material removal experiments based on AFM, TEM, and DFT calculations presents a comprehensive approach for understanding and improving CMP techniques for semiconductor materials. By elucidating the role of pH in the tribochemical removal process, this study contributes to the development of more efficient and precise CMP methods that ultimately enhance the performance of semiconductor devices.
  • Effect of Cerium Oxide Abrasives with Different Particle Sizes on the Chemical Mechanical Planarization Performance of K9 Glass
    JIANG Feng, QIAN Shanhua, QU Kesong, BIAN Da, NI Zifeng
    China Surface Engineering. 2025, 38(5): 107-118. https://doi.org/10.11933/j.issn.1007-9289.20241226002
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    K9 glass is widely used in aerospace, military, and optoelectronic applications owing to its high mechanical strength, exceptional wear resistance, superior optical transparency, and excellent thermal stability. However, as a typical hard-brittle material characterized by low fracture toughness, K9 glass is more prone to subsurface damage and crack formation during machining processes. Chemical mechanical polishing (CMP), which is recognized for its high processing efficiency, simplified equipment configuration, and cost-effectiveness, has been extensively adopted for the surface finishing of optical glasses and other hard-brittle materials. Cerium oxide (CeO2) abrasives are widely used in the surface planarization of optical glasses owing to their unique chemical reactivity with silica. Moreover, their particle size distributions play critical roles in determining both the material removal rate and surface quality. To meet the stringent requirements for a high material removal rate and superior surface quality in K9 glass polishing, this study systematically investigated the effects of five distinct particle sizes of CeO2 abrasives on the CMP performance of K9 glass, both individually and in hybrid configurations. To isolate and quantify the contributions of the chemical and mechanical actions of the abrasives, the chemical effects of the CeO2 abrasives were suppressed via the hydrogen peroxide (H2O2) treatment of the polishing slurry. This approach enables the decomposition of the total removed material into three fundamental components: mechanical action, chemical action, and synergistic interactions. In conjunction with an surface analysis using X-ray photoelectron spectroscopy (XPS), the surface chemical properties of CeO2 abrasives with varying particle sizes were systematically characterized to elucidate the material removal mechanisms of different CeO2 abrasives during a polishing process. The results showed that the material removal rate of K9 glass initially increased and then decreased as the particle size of the single CeO2 abrasive increased. In contrast, the surface roughness exhibited the opposite trend. A high material removal rate (99.53 nm / min) and low surface roughness (1.27 nm) were achieved at particle sizes of 50 and 300 nm, respectively. Moreover, the combination of CeO2 abrasives with particle sizes of 50 and 300 nm significantly improved the removal rate of K9 glass. When the mass ratio of the combination was 1∶2, the K9 glass exhibited an excellent removal rate (121.72 nm / min) and surface roughness (1.24 nm). When H2O2-treated CeO2 slurries were employed to suppress chemical interactions, neither mechanical abrasion from the polishing pad nor pure chemical action by abrasives contributes measurably to material removal. The pure mechanical action of abrasives achieved a relatively low material removal rate. Moreover, the ratio (K) of the pure mechanical removal rate to the total removal rate exhibited an increasing trend with an increase in abrasive particle size. Specifically, the values of the parameter K for abrasives with particle sizes of 20 nm and 1 μm were 3.32% and 18.9%, respectively. The results of a surface analysis via XPS revealed that the surface Ce3+ concentration decreased as the particle size of the CeO2 abrasives increased. Specifically, the Ce3+ concentrations for abrasives with particle sizes of 20 nm and 1 μm were measured at 29.5% and 25.33%, respectively. In the chemical-mechanical polishing of K9 glass, the synergistic interaction between the chemical and mechanical actions of the CeO2 abrasives served as the dominant material removal mechanism. Smaller CeO2 abrasive particles exhibited stronger chemical activity, and the surface Ce3+ concentration significantly influenced the material removal rate. Mechanical action was an indispensable component of this process. In contrast, larger abrasive particles demonstrated weaker chemical effects but exhibited enhanced mechanical grinding capabilities. The hybrid abrasive system, which effectively combined the enhanced chemical reactivity of small particles with the superior mechanical grinding capability of large particles, significantly improved the polishing performance of K9 glass. These results provide valuable theoretical and practical insights for the development of advanced polishing slurries for the precision machining of K9 glass and other optical materials.
  • Microscopic Mechanisms of Amplitude and Frequency During Ultrasonic Vibration-assisted Nanogrinding of Aluminium Nitride: A Molecular Dynamics Study
    FENG Shuaicheng, YIN Jiaqin, LIU Yang, XIAO Chen, GUO Jian
    China Surface Engineering. 2025, 38(5): 119-132. https://doi.org/10.11933/j.issn.1007-9289.20250226001
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    Ultraprecision surface grinding and polishing are crucial for manufacturing high-end aluminum nitride (AlN)-based wide-bandgap semiconductor chips and devices. When traditional ultra-precision surface processing methods such as nanogrinding are used to process AlN, the material removal rate is low, and processing-induced damage is difficult to control owing to the hard-brittle properties of AlN. It has been proven that inducing ultrasonic vibrations can increase the material removal rate and reduce subsurface damage during grinding. However, the material-removal mechanisms of ultrasonic vibration-assisted nanogrinding of AlN are not completely understood, and the influencing law and microscopic mechanisms of amplitude and frequency remain unclear. To this end, molecular dynamics simulations of ultrasonic vibration-assisted nanogrinding of AlN surfaces with single diamond abrasives under different conditions were performed to investigate the influence of amplitude and frequency on the removal of nanoscale / sub-nanoscale materials and subsurface lattice damage at the atomic level. The Vashishta potential function was used to describe the interatomic interactions within the AlN workpiece, and the Lennard-Jones potential function was used to describe the C-Al and C-N interactions between the diamond abrasives and the AlN workpiece. The microstructure of the AlN workpiece during nanogrinding was characterized by the dislocation extraction algorithm (DXA) and identify diamond structure (IDS) to discuss the effects of amplitude and frequency on subsurface lattice damage such as dislocations, stacking faults, and amorphization. Based on a comprehensive analysis of the data of the grinding force, grinding morphology, removal volume, subsurface microstructures, temperature distribution, and von Mises stress distribution, the mechanism of ultrasonic vibration-assisted nanogrinding under different amplitude and frequency conditions on the nanoscale / sub-nanoscale material removal and subsurface lattice damage at the atomic level was explored. The simulation results demonstrate that both amplitude and frequency significantly affect the grinding force, and the instantaneous tangential and normal contact areas between the diamond abrasives and AlN workpieces during nano-grinding are reduced with increasing amplitude or frequency, leading to a decrease in tangential and normal forces. Increasing the amplitude or frequency can significantly increase the material-removal volume, reduce the roughness of the grinding surface, and reduce the lattice damage in the subsurface. As the amplitude increases, the grinding force decreases linearly, the removal volume increases linearly, the dislocation distribution range decreases, and the material-removal behavior gradually changes from plastic-dominated to composite removal. When the vibration frequency reaches 1 GHz, the ultra-high-frequency vibration enhances the impact effect of the diamond abrasive on the AlN workpieces and causes the atoms to acquire high instantaneous energy, thus generating high-temperature zones at the abrasive-workpiece contact area. Owing to the more intense thermal activity of the atoms, the Al and N atoms linked via covalent bonds in these high-temperature zones can be broken more easily. Hence, material removal is facilitated, the grinding force decreases, and the removal volume increases sharply. The surface of the groove is smooth, almost reaching the atomic level of flatness, and the two sides of the groove show obvious atomic-laminar removal features. At this point, the subsurface obtains a state of almost no damage; that is, no dislocations or amorphous structures are formed except for slight stacking faults in the subsurface. In contrast, when the vibration frequencies are 10 and 100 MHz, the surface roughness is high, and many dislocations and stacking layers appear in the AlN workpiece. The analysis results suggest that ultrahigh-frequency vibration induces a localized temperature increase in the abrasive-workpiece contact area and enhances the impact of the abrasive. The research results can provide a theoretical reference for optimizing the process conditions for high-efficiency and low-damage ultraprecision grinding of hard-brittle semiconductor materials.
  • Study on the Eddy Current Detection Method for Nano-scale Metal Film Thickness Measurement
    LI Hongkai, HAN Zidong, WANG Jinlong, CHEN Mingshang, ZHANG Tong
    China Surface Engineering. 2025, 38(5): 133-146. https://doi.org/10.11933/j.issn.1007-9289.20250501001
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    As integrated circuit (IC) manufacturing technologies advance and feature sizes reduce to the nanoscale, the chemical mechanical polishing (CMP) process is imposed by increasingly stringent precision requirements. This is because slight variations in material removal can cause device failure. In particular, for metal CMP processes, achieving accurate real-time endpoint detection is essential for ensuring controllable material removal and maintaining high-quality process outcomes. Compared with other conventional endpoint detection methods based on frictional or optical principles, the eddy-current method has emerged as an optimal solution for detecting the copper film thickness variation during copper CMP process. As a non-destructive testing technique characterized by high sensitivity, rapid response, and high resistance to environmental interference, the eddy-current method provides a reliable approach for in-situ thickness measurements under complex polishing conditions. Focusing on the challenges in detecting nanoscale metal film thicknesses, a simulation model of the eddy-current sensor is established in this study by coupling an electromagnetic field and an electrical circuit. Based on the numerical simulations, the effects of fundamental parameters, including coil parameters (e.g., excitation frequency, wire diameter, inner radius, turns, and diameter-height ratio), and signal-conversion module parameters of the detection-circuit (e.g., parallel capacitance, voltage division resistance, and bridge arm resistance) on sensor performance are systematically revealed. Then the coil parameters are further optimized. And the optimal parameter values are determined specifically for CMP applications under a lift-off distance of 2 mm (corresponding to the typical thickness of a polishing pad). Subsequently, the detection circuit is optimized with emphasis on the signal-conversion module, including two fundamental circuit topologies, i.e., an LC resonant circuit and an AC bridge circuit, by determining their respective optimal values of key electrical parameters, meanwhile, the other modules, such as the signal-generation module and peak-detection module are well accomplished for a good measurement performance. Furthermore, the influences of environmental parameters, particularly lift-off distance and temperature, on the output characteristics of the detection coil is revealed. To quantify the influence of lift-off distance variations, a quantitative thickness-error assessment model is developed that correlates the film thickness, measurement error, and lift-off distance. Additionally, a decoupling calculation method is proposed by establishing a mathematical relationship correlating the output voltage, film thickness, and temperature, thereby diminishing the influence of temperature variations on the thickness measurement. Finally, a nanoscale metal film thickness eddy-current detection system is developed. The system comprises an eddy-current sensor, precision displacement modules, and a vacuum-based wafer-holding module featuring a microporous ceramic vacuum chuck. The probe is mounted on a non-metallic cantilever beam fixed to the linear-displacement module to minimize lift-off distance variations, whereas the vacuum chuck ensures stable wafer holding on the rotary-displacement module. The coordinated motion of the linear- and rotary-displacement modules enables precise thickness measurements at multiple locations on the wafer surface. According to the experimental testing at a lift-off distance of 2 mm, the self-developed detection system demonstrates a sensitivity of 1.38 mV/nm and a linearity coefficient of 0.986 9 within a measurement range of approximately 1.5 μm. And a comprehensive evaluation of the measurement performance, based on the output-voltage fluctuation and sensitivity, shows that the detection system can achieve a nanoscale precision measurement of copper film thickness over a wide range. This study facilitates advancements in high-precision in-situ detection technology for high-quality polishing processes.
  • In-situ Laser Assisted Cutting Hybrid Laser Recovery for Single Crystal Silicon
    YANG Sishuo, HUANG Weiqi, ZHANG Jianguo, XIAO Junfeng
    China Surface Engineering. 2025, 38(5): 147-156. https://doi.org/10.11933/j.issn.1007-9289.20250103001
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    Single-crystal silicon components are widely utilized in the field of infrared optics, where their surface and subsurface quality directly affects the performance and service life of the corresponding optical systems. Diamond cutting is recognized as a critical method for single-crystal silicon machining; however, it typically induces surface defects such as cutting textures, which significantly impair the performance of silicon, necessitating subsequent defect recovery. Current defect recovery techniques are generally characterized by low efficiency and insufficient precision. Thus, the efficient and accurate recovery of post-cutting surfaces remains challenging. To address this issue, this study proposes an in-situ laser-assisted cutting hybrid laser recovery technology that enables simultaneous laser recovery during the laser-assisted cutting process, thereby achieving rapid and precise surface recovery on the workpiece. Owing to the distinct functions of the two lasers, with the assisted laser responsible for heating and softening the material, and the recovery laser designated for melting the post-machined surface, simulations are carried out to simulate the heating process of single-crystal silicon under simultaneous irradiation of the assisted and recovery lasers to ensure that they do not interfere with one another in their respective heat-affected zones. Based on the simulation results, the minimum separation distance between the two lasers is determined, based on which the optical path of the device is established, guiding the design and construction of the experimental setup. Experiments are conducted on single-crystal silicon to investigate the influence of the processing parameters, including the recovery laser energy density, rotational velocity, and feed rate, on the overall machining performance. The surface quality and subsurface damage are tested. The results indicate that the energy density significantly affects the surface quality. When the energy density is insufficient, the laser recovery effectiveness is compromised, resulting in poor surface quality. Conversely, excessive energy density leads to the formation of new surface structures on the silicon wafer, which also deteriorates the surface quality. Optimal machining performance is achieved at an energy density of 0.76 J / cm². Insufficient rotational velocity results in excessive overlap of the recovery laser spots, leading to surface ablation, whereas excessive velocity induces vibrations that generate periodic waviness on the workpiece surface. Both phenomena are observed to deteriorate the machining quality. These defects are eliminated at a rotational velocity of 2 000 r / min and optimal machining performance is achieved. When the feed rate exceeded 2 mm / min, the overlap of the recovery laser along the radial direction progressively decreases with increasing feed rate. This reduction causes premature solidification of the molten pool before adequate melting and flow can occur, resulting in the formation of banded patterns and consequent degradation of surface quality. Therefore, the optimal feed rate is determined as 2 mm / min. Subsequently, the single-crystal silicon samples are processed using three distinct methods: diamond cutting, laser-assisted cutting, and in-situ laser-assisted cutting with hybrid laser recovery. Comprehensive surface and subsurface analyses are conducted to evaluate the machining outcomes. The results demonstrate that diamond cutting yields a relatively inferior surface quality with a roughness of Sa 2.854 nm. Laser-assisted cutting shows improved surface quality, achieving a roughness of Sa 2.341 nm. Notably, the in-situ laser-assisted cutting hybrid laser recovery significantly enhances the surface quality, reducing the roughness to Sa 1.587 nm. Raman spectroscopy further reveals that the in situ laser-assisted cutting hybrid laser recovery technology not only effectively recovers amorphous defects on the silicon surface, but also eliminates the residual stress damage induced during the machining process. These results demonstrate that the in-situ laser-assisted cutting hybrid laser recovery is an efficient and accurate method for surface machining. which is capable of obtaining sub-nanometer single-crystal silicon surfaces without the need for additional processes.
  • Research on Static Characteristics of Porous Thrust Bearings for Wafer Grinding Machines
    SHI Minghui, ZHANG Guolong, DU Peng, CHEN Jiangyi, HU Hongyang
    China Surface Engineering. 2025, 38(5): 157-170. https://doi.org/10.11933/j.issn.1007-9289.20250324002
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    To address the performance degradation of grinding spindles in wafer-grinding machines caused by the deformation of the restrictor material, the effect of graphite material deformation on the static characteristics of porous thrust bearings was investigated. Based on Darcy’s law, the Navier-Stokes equation, and flow balance equations, a static characteristic analysis model of a porous thrust bearing was established, and a deformation model of a porous restrictor coupled with non-uniform gas-film pressure in the bearing clearance was established. Using the established numerical model, the effects of the thickness and elastic modulus of porous graphite on the dimensionless gas-film pressure and deformation on the bearing surface of a porous thrust bearing under the effect of fluid-solid interactions were investigated, which revealed the interaction mechanism between the gas-film pressure and the deformation of porous graphite. The results indicate that as the porous graphite becomes thinner, its throttling ability diminishes, thus resulting in increased gas-film pressure within the bearing clearance and greater deformation of the porous graphite. Consequently, this deformation increases the gas-film thickness, thus causing the gas-film pressure to reduce significantly. The deformation of porous materials exhibits an inverse relationship with the elastic modulus and progressively diminishes as the elastic modulus increases. Therefore, the increasing elastic modulus of the porous graphite results in a smaller increase in the thickness of the gas film caused by deformation, thus resulting in a lower reduction in the gas-film pressure and an asymptotic approach to the non-deformation solution. By calculating the load-carrying capacity and volume flow rate of bearings with different porous-graphite thicknesses and elastic moduli, the effects of the material properties of porous graphite and the bearing operating parameters on the static characteristics of porous thrust bearings under the effect of fluid-solid interactions were investigated. The results indicate that as the bearing clearance decreases and the gas supply pressure increases, the deformation of the porous graphite increases, thus causing the load-carrying capacity to decrease significantly and the volume flow rate to increase considerably. Additionally, material deformation imposes a substantial and non-negligible effect on the static characteristics of bearings. To minimize the effect of material deformation on the static characteristics of the bearing, the optimal bearing clearance and gas supply pressure should be maintained at 20 μm and 0.5 MPa, respectively. The higher the permeability coefficient, the greater is the reduction in the bearing capacity and the increase in the volume flow rate caused by the deformation of porous graphite. Conversely, a reduction in the permeability coefficient corresponds to a diminished effect of material deformation on the static characteristics. Based on theoretical analysis, 5×10-9 mm2 is identified as the optimal permeability coefficient. The thinner the porous graphite, the greater is the reduction in the bearing capacity and the increase in the volume flow rate of the bearing. However, an excessively thick porous graphite limits the improvement in the bearing capacity. Therefore, controlling the enhancement to the porous-graphite thickness effectively mitigates the effect of material deformation on the bearing static characteristics. A comprehensive evaluation of the static performance parameters yields an optimal thickness of 4 mm. Under a lower elastic modulus, the porous-graphite deformation significantly affects the static characteristics. As the elastic modulus of porous graphite increases, the effect of material deformation on the static characteristics of the bearings decreases. To prevent the static performance of porous thrust bearings from being degraded substantially, the elastic modulus of porous-graphite materials should be maintained at a minimum of 20 GPa. This study provides theoretical support for improving wafer-grinding quality and aerostatic grinding-spindle performance.
  • Removal Mechanism of Single-crystal Silicon Carbide by Ultrasonic-assisted Photocatalytic Polishing
    TIAN Zhuangzhi, BAN Xinxing, BA Wenlan, ZHU Jianhui, WANG Ningchang, HUI Zhen, LI Zhengxin
    China Surface Engineering. 2025, 38(5): 171-181. https://doi.org/10.11933/j.issn.1007-9289.20250122001
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    Single-crystal silicon carbide (SiC), as a wide-bandgap semiconductor material with excellent properties, is widely used in high-power electronic devices and optoelectronic fields. However, its high brittleness, extreme hardness, and strong chemical inertness pose significant challenges for achieving efficient and low-damage polishing. Chemical mechanical polishing (CMP) cannot meet industrial efficiency requirements owing to its slow reaction kinetics. Therefore, this study introduces ultrasonic vibration into the photocatalytic chemical mechanical polishing (PCMP) method to investigate the synergistic enhancement mechanism of ultrasonic-assisted photocatalysis and the material removal mechanism under multi-energy field interactions, with the aim of advancing the development of multi-energy field collaborative polishing technology. Three different experiments were designed to evaluate the effects of ultrasonic frequencies (0, 22, 25, 28, and 40 kHz) on the chemical and mechanical performance. This study combined photocatalytic oxidation with ultrasonic vibration, using nano-TiO₂ as a catalyst under UV irradiation to induce cavitation effects. The Oxidation performance characterization tests utilized a methyl orange solution as an indicator, with the decolorization time of the polishing solution under ultrasonic-assisted photocatalytic conditions used to assess oxidative strength being shorter, indicating a stronger oxidation capability. The static corrosion tests involved immersing the SiC samples in the polishing solution for 2 h under ultrasonic-assisted photocatalytic conditions. The resulting oxide layers were quantified using scanning electron microscopy and X-ray photoelectron spectroscopy. Ultrasonic-assisted PCMP experiments were conducted using SiO₂ abrasive slurry for 2 h, with the material removal rates and surface roughness measured to evaluate polishing performance. At 22 kHz ultrasonic vibration, the methyl orange decolorization time was 229 s, the oxygen content on the corroded surface reached 2.94at.%, the material removal rate was 503.47 nm / h, and the surface roughness was 48.28 nm. Compared with photocatalytic oxidation alone, ultrasonic assistance reduced the decolorization time by 117.90%, increased the oxygen content by 215.96%, improved the material removal rate by 52.63%, and reduced the surface roughness by 91.30%. The electron-hole pairs generated by the photocatalyst under illumination effectively promoted the formation of highly oxidative radicals (e.g.,·OH) in the reaction environment, accelerating the formation of oxide layers. The·OH in the polishing solution oxidized the surface, forming oxide layers primarily composed of Si and C oxides, which exhibited significantly lower hardness, strength, and bonding strength compared with the original SiC surface, thereby allowing easy removal using diamond or silica abrasives. Ultrasonic vibration enhanced both the chemical oxidation and mechanical removal stages of the polishing process. During ultrasonic propagation in liquids, cavitation bubbles formed and collapsed rapidly upon reaching a critical size during the compression cycles, generating localized high-energy microenvironments with temperatures exceeding 5 000 K and pressures up to 1 000 atm. Ultrasonic effects accelerated the mass transfer among the reactants, catalysts, and radicals, reduced the diffusion resistance, rapidly removed intermediate products generated during photocatalytic reactions, prevented reaction blockage, promoted electron-hole pair separation, reduced recombination rates, increased·OH concentration, and significantly improved the photocatalytic oxidation efficiency. The collapse of the cavitation bubbles enhanced the kinetic energy of the catalysts and abrasives, increasing the contact frequency and efficiency between the workpiece, catalysts, and abrasives, thereby improving the oxidation rate and mechanical removal efficiency of SiC. Ultrasonic vibrations also promoted the uniform distribution of photocatalysts and abrasives, eliminated catalyst agglomeration, increased the reactive surface area, enhanced the photocatalytic efficiency, and improved the surface uniformity and consistency. In addition, the localized high-temperature environments generated by cavitation bubbles further enhanced the chemical reactions. Notably, lower ultrasonic frequencies exhibited stronger cavitation effects, significantly improving the efficiency of ultrasonic-assisted PCMP. Owing to the synergistic effects of ultrasonic vibration, photocatalysis, and mechanical forces, the wear characteristics of the surface were significantly different from those after traditional grinding and polishing. Ultrasonic action improves the fracture toughness, facilitates plastic removal, and reduces subsurface damage. Therefore, integrating ultrasonic vibration into PCMP enhances the photocatalytic activity and abrasive kinetic energy, increases the oxidation rates and removal efficiency, and enables more efficient polishing of single-crystal SiC.
  • Research Progress in the Engineering Applications of Bionic Anti-icing Coating
    TANG Yuting, TIAN Pan, WANG Yang, LI Sheng, LIU Jiaqi, LIU Lanxuan, LI Dongdong, QIN Weihua, CHEN Wenrui
    China Surface Engineering. 2025, 38(5): 182-197. https://doi.org/10.11933/j.issn.1007-9289.20241022001
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    The accumulation of surface ice poses significant safety risks for operating engineering machinery, which can potentially lead to severe security incidents and economic losses. Presently, the pursuit of stable and effective anti-icing techniques for engineering applications is a significant scientific problem. Conventional anti-icing strategies, such as the utilization of chemical anti-icing agents, thermal anti-icing, and mechanical anti-icing, are characterized by low efficiency, high costs, and environmental unfriendliness. In response to these issues, researchers actively explored biological organisms with anti-icing properties in nature and proposed multiple strategies based on the principles of bionics, such as bio-inspired superhydrophobic anti-icing coatings, bio-inspired super-slippery anti-icing coatings, and bio-inspired antifreeze protein anti-icing coatings. Bio-inspired anti-icing coatings showed excellent anti-icing performance with low costs and low energy consumption, providing a foundation for the large-scale engineering application of anti-icing coatings. This review summarizes the latest research progress of bio-inspired anti-icing coatings for engineering applications, describing the anti-icing mechanisms and the preparation processes of anti-icing coatings, respectively. The three primary types of examined bionic coatings are superhydrophobic surfaces (SHS), slippery liquid-infused porous surfaces (SLIPS), and antifreeze protein (AFP) coatings. Superhydrophobic anti-icing coatings are inspired by the self-cleaning properties of the lotus leaf, which exhibits remarkable water-repellence because of its micro- and nanostructured surface. Superhydrophobic coatings effectively deter ice nucleation by minimizing water contact and reducing surface energy. However, it remains the challenges of improving their durability and resistance to environmental, particularly in industrial settings. Super-slippery anti-icing coatings modeled after the slippery surfaces of pitcher plants use a liquid lubricant trapped within a porous structure to create a non-stick surface. This design prevents ice from adhering to the coated surface, even under dynamic and fluctuating conditions. Super-slippery coatings demonstrate exceptional anti-icing performance; however, their dependence on specific lubricants raises concerns related to environmental compatibility and long-term maintenance. The antifreeze protein anti-icing coatings mimic the antifreeze proteins found in Antarctic fish, which inhibit ice crystal growth at the molecular level. Although antifreeze protein anti-icing coatings are promising in laboratory settings, their scalability and cost-efficiency for industrial applications remain areas requiring further exploration. This review encapsulates a variety of methodologies employed for evaluating the anti-icing efficacy of coatings, which are designed to replicate the stringent environmental conditions encountered in practical scenarios and for quantifying the resistance to ice formation and adhesion. Laboratory-based assessments, which include freeze-thaw cycle experiments, measurements of ice adhesion strength, and ice accretion delay tests, are delineated, thereby providing a comprehensive overview. Complementary to these, outdoor environmental experiments are discussed for contributing to validating the performance of the coatings under real-world circumstances. Further, this review addresses deficiencies inherent in the current assessment protocols and advocates for standardizing evaluation methods to guarantee the precise and consistent measurement of coating performance. This review provides an in-depth examination of the construction technology research pertaining to biomimetic anti-icing coatings and delineates the intricate process of preparing these coatings, encompassing the selection of raw materials, optimization of ingredient ratios, and coating methodologies. Further, this review presents a series of application tests that demonstrate the effectiveness of bionic anti-icing coatings in multiple sectors, such as aviation, construction, and transportation infrastructure. These tests affirm the high efficiency and reliability of the coatings in inhibiting ice formation, validating their utility in preventing hazards associated with icing in these critical domains. These studies advanced the process of bio-inspired anti-icing coating engineering applications and improved efficiency and stability in practice. Finally, based on the current research status, this review summarized the challenges and limitations of bio-inspired anti-icing coatings in the process of engineering applications, aiming to provide valuable references and insights for promoting the engineering applications of anti-icing coating.
  • Review on the Preparation and Regulation of Tribological Properties of Diamond-like Carbon Films
    HAN Bingyuan, XU Jianfei, DU Wenbo, ZHAO Yonglin, CUI Fangfang, LI Han, ZHU Sheng
    China Surface Engineering. 2025, 38(5): 198-214. https://doi.org/10.11933/j.issn.1007-9289.20240902001
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    Diamond-like carbon (DLC) films are renowned for their exceptional wear resistance, low friction factor, and high hardness, which have led to their widespread application in the automotive, aerospace, and mechanical manufacturing industries. Various advanced techniques have been developed to control the properties of DLC films and prolong the service lives of mechanical components under wear and corrosion conditions, thereby enhancing their performance. The body of research in this field is continuously being enriched and refined. However, there is a scarcity of comprehensive review papers, which are crucial for guiding the development of the entire industry and academic domain. In response to this need, this study systematically summarizes the existing research on the wear-resistant properties of DLC films from both domestic and international perspectives, focusing on aspects such as preparation technology, process parameter optimization, modification through element doping, gradient construction, and surface texturing. A comprehensive aggregation of the research results strongly suggests that the meticulous adjustment of the process parameters is indispensable for marked enhancements in the hardness and wear resistance of DLC coatings. Element doping can improve the structure and properties of DLC films to achieve high elastic recovery as well as low friction and wear; gradient construction can strengthen the adhesion, hardness, and wear resistance of DLC films; and surface texturing can enhance the tribological performance of DLC films. Therefore, by finely controlling the process parameters, types and contents of doping elements, and design of surface structures, the microstructures of DLC films can be effectively altered to achieve an increase in the wear resistance, a reduction in the friction coefficient and wear rate, and enhanced adhesion, hardness, and wear resistance. These improvements are beneficial for extending the service lives of mechanical components under severe operating conditions. By comprehensively adjusting the manufacturing processes and other strategies for DLC films, this study achieves an overall upgrade in wear-resistant performance, thus filling the void in the industry for a systematic review on the optimization of DLC film properties. The research summarized in this study covers a range of deposition techniques, including physical vapor deposition (PVD), chemical vapor deposition (CVD), and plasma-enhanced chemical vapor deposition (PECVD), which are vital for achieving the desired film properties. The optimization of process parameters, such as the substrate temperature, deposition pressure, ion energy, and gas flow rates, is discussed, as all these parameters are critical for controlling the structure and performance of the film. The role of element doping in modifying the properties of films is investigated, with a focus on the use of transition metals, rare earth elements, and other alloying agents to enhance certain characteristics of DLC films. Furthermore, the study explores the concept of gradient construction, where the compositions and structures of films are varied throughout their thicknesses to create a gradient that can improve adhesion to the substrate and enhance mechanical properties. The study also addresses surface texturing, which involves the creation of micropatterns on the surface of a film to reduce friction and wear, which is a feature of particular importance for applications in which tribological performance is critical. In conclusion, this study provides a thorough overview of the research and development in DLC film technology by highlighting the key areas that are essential for the advancement of the field. This study underscores the importance of a holistic approach to the design and fabrication of DLC films and emphasizes the interplay among preparation techniques, process optimization, material modification, and surface engineering to achieve superior wear-resistant performance. This comprehensive review is significant in guiding future research and fostering innovation in the application of DLC films across various industries, and it serves as an essential reference for the further development of related technical fields.
  • Flame Spraying Graphite Modified CF / PEEK Composite Coating and its Tribological Properties
    LI Yupeng, XIE Jiaqi, ZHANG Shuolei, LIANG Taihe, LEI Mingkai
    China Surface Engineering. 2025, 38(5): 215-225. https://doi.org/10.11933/j.issn.1007-9289.20240530001
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    Flame spraying polymer composite coatings is an effective method by which to improve the surface properties of metal parts. The use of self-lubricating fillers to reduce the friction and wear of polymer composite coatings is beneficial for expanding the applications of moving mechanical parts under harsh conditions. CF / PEEK composite coatings with graphite fillers at mass fractions of 1wt.%, 2wt.%, and 5wt.% were prepared on 17-4PH steel substrates using flame spraying technology. The effects of the graphite content on the cross-sectional morphology, porosity, crystallization behavior, thermal performance, surface hardness, tribological properties, and wear mechanism of the flame-sprayed CF / PEEK composite coatings were studied using SEM, XRD, FTIR, TGA, nanoindentation, and tribological tests. The results showed that the porosity of the composite coatings first decreased and then increased with increasing graphite filler content. The porosities of the flame-sprayed composite coatings with 2wt.% graphite fillers were the lowest at 2.13%, which is 23.9% lower than those of the CF / PEEK coatings. The high graphite filler content causes an increase in the porosity, owing to the poor stacking of the melted PEEK particles during flame spraying. Graphite fillers with 5wt.% content led to little thermal degradation of the PEEK in flame-sprayed composite coatings. The crystallinity of the composite coatings initially increased and then decreased as the graphite filler content increased. The graphite fillers had little effect on the thermal weight loss rate of the composite coatings but increased the initial decomposition temperature and the temperature corresponding to the maximum weight loss rate, thereby enhancing the thermal stability of the flame-sprayed composite coatings. Low-content graphite fillers promote the surface hardness of the flame-sprayed composite coatings. The surface hardness of the composite coatings with 2wt.% graphite fillers is the highest at 0.326 GPa, which is 9.86% higher than those of the CF / PEEK coatings. A graphite filler content of 5wt.% led to a decrease in surface hardness, owing to the high porosities of flame-sprayed composite coatings. The friction factor of the flame-sprayed composite coatings initially increased and then decreased with increasing graphite filler content. The high friction factor of the flame-sprayed composite coatings with low graphite filler content could be attributable to the high bearing capacities of the composite coatings with high surface hardness. The friction factor of the flame-sprayed composite coatings with 5wt.% graphite fillers were the lowest at 0.291. The lubrication effect of the graphite fillers and high porosity of the composite coatings resulted in a low friction factor. The specific wear rate of the flame-sprayed composite coating first decreased and then increased with an increasing graphite filler content. The specific wear rates of flame-sprayed composite coatings with 1wt.% graphite was the lowest at 0.84×10-6 mm3 / (N·m), which is 37.8% lower than that of the CF / PEEK coating. The lubrication effects of graphite fillers and the high surface hardness of the flame-sprayed composite coatings with graphite fillers at low contents were beneficial for achieving low specific wear rates. The fatigue wear and abrasive wear of the flame-sprayed composite coatings with 1wt.% and 2wt.% graphite fillers were reduced, and the wear resistances of the coatings were improved. However, the adhesive wear of the flame-sprayed composite coating with 5wt.% graphite fillers increased, showing more severe wear. Graphite and CF fillers were used to modify the flame-sprayed PEEK composite coatings. Hence, the flame-sprayed composite coatings exhibited significant improvements in their mechanical and tribological properties. Moreover, the wear resistance mechanisms of the flame-sprayed composite coatings are discussed. Therefore, flame-sprayed CF / PEEK composite coatings with graphite fillers exhibit engineering application potential for friction reduction and wear resistance.
  • Effect of CNTs Content on the Microstructure and Properties of Laser Cladding Wear-resistant and Corrosion-resistant Coatings
    WU Zhengjiang, LI Shuaibing, WEI Xiaoqiang, DU Pengcheng, YU Siliang, LIU Yiou, HE Xueming, PANG Xuming, PU Jibin
    China Surface Engineering. 2025, 38(5): 226-237. https://doi.org/10.11933/j.issn.1007-9289.20240529001
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    With the implementation of the maritime power strategy, corrosion-wear coupling damage in marine equipment parts is becoming increasingly serious and has become a bottleneck in scientific research, restricting the development of marine equipment in China. Amorphous alloys have attracted considerable attention because of their excellent chemical, physical, and mechanical properties owing to the absence of defects such as dislocations and grain boundaries. Fe-based amorphous alloys are favored in petroleum, chemical, and marine engineering owing to their high hardness, excellent wear resistance, and good corrosion resistance. Considering an amorphous nanocrystalline coating with superior wear resistance as the research focus, a new ultrahigh-speed laser cladding technology was explored. Fe-based amorphous alloy coatings with varying carbon nanotube (CNT) contents were prepared on the surface of Q235 steel using coaxial powder-feeding laser cladding after mixing nickel-plated CNTs and Fe-based amorphous powder through a ball milling process. The effects of CNTs on the microstructure, phase composition, mechanical properties, and tribocorrosion properties of the coatings were investigated. With an increase in CNT content, the crystallinity of the coating increases, while the amorphous content decreases. The α-Fe solid solution and Cr23C6 and Cr12Fe36Mo10 intermetallic compounds appear on the coating. When the CNT content exceeds 0.25wt.%, Cr7Ni3 appears on the coating. When the CNT content exceeds 0.5wt.%, Fe2C also appears on the coating. The optimal CNT content for enhancing coating performance is 0.25wt.%, with a microhardness reaching 1 024.55 HV0.2 Under the combined effects of friction and corrosion, the friction factor generally increases with higher CNT content; however, the 0.25wt.% CNT coating exhibits a lower friction factor. Additionally, the bridging behavior of nickel-plated CNTs at cracks inhibits material loss and enhances the corrosion resistance of the coating. The appropriate addition of CNTs effectively improves both the wear and corrosion resistance of the coating. Furthermore, the study explored the corrosion-wear interaction damage behavior of the coating, revealing the physical and chemical mechanisms of corrosion wear in an amorphous-nanocrystalline coating within a marine environment. The coating demonstrates a low friction factor and wear rate under open-circuit potential (OCP) and cathodic protection (CP) conditions. Material loss is influenced by the synergistic effects of friction and corrosion, with the acceleration of wear by corrosion being the primary factor in coating degradation. During the friction and wear processes, galvanic corrosion occurs between worn and unworn areas, where the worn area acts as the cathode and the unworn area as the anode. The pressure exerted by the grinding ball exceeds the yield strength of the coating, leading to plastic deformation and crack formation. The shear force at the contact point between the grinding ball and the coating causes material to peel off and delaminate, forming plaques. The detached layer adheres to the contact point during reciprocating motion, where further shearing removes material from the coating surface. Over time, these detached patches accumulate and cover portions of the wear scar, leading to stratification. The goal of this study was to address the common issue of corrosion-wear coupling damage in marine equipment components and provide a theoretical foundation for the engineering application of amorphous-nanocrystalline coatings in marine environments. The development of coatings with superior wear and corrosion resistance is crucial for ensuring the long-term, reliable operation of key mechanical moving parts in marine equipment.
  • Effects of Ultrasonic Surface Rolling Processing and Plasma Nitriding on Tribological Properties of 4Cr13 Stainless Steel
    LUO Xiaoshuang, PAN Lin, DUAN Haitao, TU Jiesong, LIU Lian, ZHAN Shengpeng, JIA Dan
    China Surface Engineering. 2025, 38(5): 238-249. https://doi.org/10.11933/j.issn.1007-9289.20240626001
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    4Cr13 stainless steel has good corrosion and oxidation resistance and has been widely used in the aviation, aerospace, rail transit, and shipbuilding industries. However, owing to its low hardness and poor wear resistance, it cannot satisfy the usage requirements under harsh working conditions. Therefore, to improve the surface properties of 4Cr13 stainless steel and expand its application range, it must be subjected to a surface strengthening treatment. Plasma nitriding (PN) is widely used for the surface strengthening of metal components. After PN treatment, the surface of a metal material typically exhibits high hardness, good wear resistance, and high fatigue strength. However, to obtain a deeper nitriding layer and higher surface hardness, a longer nitriding time and higher nitriding temperature are often required, which not only wastes energy and increases production costs, but also leads to deterioration of the inherent properties of the metal components. Surface severe plastic deformation (S2PD) treatment can make the grains of the metal material surface finer than those of the nanocrystals, and the grain boundaries and dislocation density of the nanocrystal layer increase. This can increase the diffusion channels of nitrogen atoms and lower the activation energy, thereby effectively increasing the nitrogen atom penetration rate. Ultrasonic surface rolling processing (USRP) is an ideal pre-treatment process for the S2PD process combined with PN surface strengthening technology, which can not only form a thicker nanograded microstructure on the surface of metal materials, but also significantly reduce their surface roughness (Ra), achieving “one-step” nanostructuring and finishing. In this study, USRP is used as a pre-treatment process for PN to perform ultrasonic surface rolling and ion implantation nitriding composite strengthening (USRP+PN) on 4Cr13 stainless steel. The microstructure, microhardness, distribution of nitrogen, and tribological properties of 4Cr13 stainless steel are studied using scanning electron microscopy (SEM), energy dispersive spectrometry (EDS), an electron probe X-ray micro-analyzer (EPMA), an optical microscope, a Vickers hardness tester, and a friction and wear tester after USRP+PN treatment. The results show that, compared with the untreated (UN) sample, the Ra of 4Cr13 stainless steel decreases after being subjected to USRP treatment with four and six passes (USRP4 and USRP6), and serious plastic deformation occurs on the surface. The grains are refined and a nanograded microstructure is formed on the surface. The plastic deformation layer of the USRP6 sample is deeper, and the grains are finer. The Ra of the UN, USRP4, and USRP6 samples are 1 159.7, 80.1, and 401.3 nm, respectively. The depth of the surface plastic deformation layer of the USRP4 and USRP6 samples are 181.1 and 253.4 μm, respectively. The surface grain sizes of the UN, USRP4, and USRP6 samples are 7.5, 0.7, and 0.5 μm, respectively. Compared with the UN sample, the surface hardness of the USRP4, USRP6, UN+PN, USRP4+PN, and USRP6+PN samples increases by 34.56%, 37.01%, 328.63%, 352.53%, and 358.21%, respectively. The depth order of the nitriding layer is UN+PN < USRP4+PN < USRP6+PN, and that of the wear rate is USRP6+PN < USRP4+PN < UN+PN < USRP4 < USRP6 < UN. The wear rates of the USRP6+PN and UN+PN samples are 3.5% and 4.9% of the UN sample, respectively. USRP and PN treatments can play a synergistic role in improving the wear resistance of 4Cr13 stainless steel. The wear mechanism of the 4Cr13 stainless steel includes abrasive, adhesive, and oxidation wear. Adhesive wear is dominant in the UN and USRP samples, whereas abrasive wear is dominant in the UN+PN and USRP+PN samples. USRP as a pre-treatment process can effectively improve the efficiency of PN, and the USRP+PN composite strengthening treatment provides a new approach for improving the wear resistance of 4Cr13 stainless steel.
  • pH-responsive Self-healing Coatings of Chitosan Crosslinked Encapsulated Tubular Silicon Dioxide
    SHI Hao, ZHANG Peiqi, CHU Guiwen, ZHANG Jiankai, SONG Liying, JIANG Quantong, MA Fubin
    China Surface Engineering. 2025, 38(5): 250-263. https://doi.org/10.11933/j.issn.1007-9289.20240806002
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    Corrosion is considered the most critical cause of material failure in industries that utilize metallic parts. Organic coatings are often used to overcome corrosion challenges by limiting contact between metallic surfaces and aggressive environments. During operation, protective coatings may be damaged, which could allow aggressive media to penetrate the base metals and initiate corrosion. Self-healing smart coatings have been developed to overcome these limitations. In this study, tubular mesoporous silica (T-mSiO2) encapsulated by chitosan (CS) with a pH-responsive release of the corrosion inhibitor 5-ethyl-1,3,4-thiadiazol-2-amine (ETDA), denoted by CS-T-mSiO2-ETDA, was prepared and employed to promote the long-term anticorrosion properties of the coating. The hollow structure of T-mSiO2 was used to load the ETDA, which was sequentially encapsulated on the outer surface of T-mSiO2, to serve as an on/off switch for the controlled release of the corrosion inhibitor. When the substrate is damaged and corrosion occurs, the local microenvironment at the scratched location becomes acidic, the CS outside the T-mSiO2 tube expands, the control release switch fails, and the corrosion inhibitor inside the tube is released. When the corrosion inhibitor is released to form a protective film that inhibits further corrosion, the local environment at the damaged location becomes alkaline, the CS outside the T-mSiO2 tube shrinks, and the control release switch closes, thus preventing the corrosion inhibitor from being released. A series of characterizations and tests were conducted to verify the rationality of the CS-T-mSiO2-ETDA preparation and its self-healing performance when added to the coating. Fourier transform infrared spectroscopy (FTIR) was used to confirm the successful loading of ETDA onto T-mSiO2. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) were employed to observe the morphological structures of T-mSiO2 and CS-T-mSiO2-ETDA. A thermogravimetric analysis (TG) revealed that T-mSiO2 carried approximately 18wt.% of ETDA and that T-mSiO2 encapsulated with CS accounted for approximately 12wt.% by mass. The corrosion inhibition ETDA released from the loaded T-mSiO2 was assessed using electrochemical impedance spectroscopy (EIS) in a 3.5wt.% NaCl solution. The self-healing properties of the coatings were tested using EIS. An analysis of the impedance values at 0.01 Hz showed that the self-healing ability of the coatings reached a maximum on the 11th day and that the repairing effect of the added CS coatings was significantly higher than those of the unadded coatings. The electrochemical impedance data were fitted using ZSimpWin, and the analysis of the fitting results showed that the self-healing coatings had a better corrosion-protection capability. Furthermore, the pH responsiveness of the CS-T-mSiO2-ETDA coatings was verified by EIS tests at different pH values to determine the pH response properties of CS-T-mSiO2-ETDA more accurately via three drug release kinetic models. Compared with the zeroth-order and first-order release models, the fit (R2) of the Korsmeyer-Peppas release model was closer to 1; therefore, the Korsmeyer-Peppas release model was the best model. The fitting results show that the corrosion inhibitors have higher release rates in acidic environments (pH=5). Energy dispersive spectrometry (EDS) and scanning Kelvin probe (SKP) tests were conducted to confirm that the CS-T-mSiO2-ETDA coating had a desirable self-repairing ability after damage. The obvious reduction in the copper content in the scratches in the EDS test before and after self-healing as well as the disappearance of the potential valley in the scratches in the SKP test proved that the coating exhibited good self-healing performance. Combining the results of multiple tests showed that the prepared coatings have excellent self-healing properties and pH-controlled release abilities, which provides a novel idea for the corrosion protection of marine metal equipment and is expected to extend the service life of marine equipment.
  • Evolution Characteristics and Mechanism Analysis of Micro-morphology of Magnesium Alloy Substrate Surface Cleaned by Multi-system Laser
    ZHENG Wanqing, WANG Sijie, LI Zhe, WANG Zhonglong, YIN Fengshi
    China Surface Engineering. 2025, 38(5): 264-275. https://doi.org/10.11933/j.issn.1007-9289.20240923003
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    In the field of industrial production, traditional cleaning technologies, which include mechanical friction, high-pressure water jet, chemical reagents, and ultrasonic cleaning, can no longer meet the current high standard requirements for product surface quality. Laser cleaning technology exhibits high efficiency, non-contact, and environmental protection, and its advantages of high precision and no pollution, make it show great application potential in the field of metal surface treatment. In this study, the continuous-pulse composite multibody laser cleaning method is innovatively adopted, which aims at significantly improving the cleaning efficiency and accurately controlling the surface morphology of the substrate. The cleaning effect of the continuous-pulse composite laser on the surface paint layer of AZ31B magnesium alloy was evaluated, and the effects of different laser power combinations, scanning speed, and scanning spacing on the micro-morphology of the substrate surface were analyzed. The experimental results indicate that the paint layer cannot be effectively removed when the laser power is too low or the scanning speed and spacing are too large. However, the surface of the substrate may be damaged when the laser power is too high or the scanning speed and spacing are too small. Based on the pre-experimental results, we determined six paint removal parameters with different laser powers under the conditions of scanning speed of 3 000 mm / s and scanning interval of 0.06 mm. The test and analysis results show that the paint layer on the surface of magnesium alloy can be removed efficiently and without damage to the surface of magnesium alloy substrate under the combination of the process parameters of “continuous laser power of 90 W+ pulsed laser power of 30 W”. We observed that different laser power combinations can form various micro-morphology states on the substrate surface by adjusting the laser cleaning process parameters such as surface remelting morphology under the process parameter combination of “continuous laser power 100 W + pulsed laser power 35 W”, microstructure surface morphology under the process parameter combination of “continuous laser power 110 W + pulsed laser power 40 W” and “continuous laser power 120 W + pulsed laser power 45 W”. In this study, advanced equipment such as optical microscope (OM), scanning electron microscope (SEM), energy dispersive spectrometer (EDS), laser confocal microscope (LSCM), and Fourier infrared spectroscopy (FT-IR) were used to analyze the micro-morphology, composition, and surface roughness of the substrate surface after cleaning. This revealed that different laser power combinations had an important effect on the evolution of the substrate surface morphology. With the help of high-speed camera and thermal infrared equipment, we monitored the paint layer on the surface of magnesium alloy by multisystem laser cleaning in real time, which further revealed the multieffect coupling mechanism such as a thermal effect, mechanical effect, and plasma impact in the process of multisystem laser cleaning, providing a strong support for the high-quality and efficient cleaning of the paint layer on the surface of magnesium alloy and the process control of the micromorphology of the substrate surface. In this study, a new type of continuous-pulse composite laser cleaning technology was successfully developed, which significantly improved the cleaning efficiency and realized the accurate control of the micro-morphology of the substrate surface. The development of this technology provides a new direction for the progress of metal surface treatment technology, and it has important industrial application value in improving cleaning efficiency and surface quality control. This study not only improves the cleaning efficiency, but also provides a new idea for developing a magnesium alloy surface treatment technology, which has important scientific significance and an application prospect for developing metal surface treatment technology.
  • Numerical Simulation and Surface Quality Optimization of ABS Plate by Pulsed Laser Marking
    CAI Song, CHEN Da, TAO Nengru, WEN Yuebing, BAI Bin, HEI Zhijian, HUANG Zhan
    China Surface Engineering. 2025, 38(5): 276-289. https://doi.org/10.11933/j.issn.1007-9289.20240129002
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    Laser marking is a contactless green machining technology that offers several advantages including low consumption, high efficiency, high precision, controllability, and flexibility. These characteristics make laser processing suitable for surface patterning of materials. The results of this study indicate that controlling the laser process parameters is crucial for achieving a high-quality surface finish. To identify the optimal laser parameters for laser processing of acrylonitrile-butadiene-styrene (ABS), a one-dimensional physical heat transfer model for pulsed laser marking of ABS materials was developed in this study. This model considers the thermophysical properties of the materials and the energy accumulation effect. The dynamic evolution of the laser power and heat transfer temperature of the pulsed laser marking of the ABS material was obtained from numerical simulations of the model. From these results, the power range in which the material underwent slight ablation and achieved the maximum rate of mass loss was determined. The numerical simulation results and analysis of the cumulative energy effect were used to set the experimental parameters, including laser scanning speed, laser frequency, and laser power. Experiments were conducted to investigate the efficacy of laser-marking ABS using a CO2 pulsed laser. The experiments involved measuring the surface roughness of the processed area of the sheet, determining the marking depth, and examining the microscopic topography. The results of the roughness experiments showed that the surface roughness of the ABS sheet changed abruptly as power increased. The power threshold under experimental conditions was 2.8 W. This phenomenon demonstrates that the temperature in the laser-irradiated area of the plate reached the gasification temperature of the material at this laser power. Consequently, the oxidation-inhibiting component was no longer able to function, leading to rapid oxidative decomposition of the material. The energy accumulation effect during laser processing was found to be a key factor affecting the temperature distribution of the sheet and the final processing results. The strength of the cumulative energy effect is related to laser parameters such as laser scanning speed, laser frequency, spot diameter, and laser defocusing amount. When the ABS plates were processed at an appropriate laser power, the laser-marked plate area exhibited a shallow-etched micromorphology with a white bulge structure under a three-dimensional super-depth-of-field system. When the laser power was constant, the scribing test results showed that changes in laser scanning speed and frequency affected the straightness of the scribed lines. The buildup of soot and carbon black on the plate during the laser marking process was effectively removed using ultrasonic cleaners. Theoretical and experimental studies showed that for a laser frequency of 20 kHz, laser spot diameter of 100 μm, laser scanning speed of 100 mm/s, and laser power range between 2 and 2.8 W, the laser-marking ABS surface quality was excellent, presenting a very small number of pollutants. Based on the experimental laser process parameters for marking ABS sheets, the results of this study are consistent with those of the numerical analysis. The accuracy of the heat transfer model and the feasibility of its application in optimizing laser process parameters were experimentally verified.
  • Dynamic Behavior of Flexible Aggregation of Magnetic Abrasive Particles in the Magnetic Abrasive Finishing Process
    LIU Shuaihang, CAO Rui, HAN Bing, YING Jun, YANG Haiji
    China Surface Engineering. 2025, 38(5): 290-300. https://doi.org/10.11933/j.issn.1007-9289.20240911002
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    Magnetic abrasive finishing (MAF) is a widely used technique in precision manufacturing, which is particularly effective for complex surfaces that require high-quality finishes. However, simulating the behavior of magnetic abrasive particles within this process poses significant challenges. This difficulty arises because of the magnetic interactions between particles, the effect of external magnetic fields, and the frequent contact among particles. These factors extend computation times and limit the accuracy of existing simulations. This study aims to address these challenges by developing an advanced numerical model that incorporates both magnetic forces and inter-particle dynamics. This model aims to offer a more precise simulation of the MAF process by capturing the micro-scale motion, displacement, and rotational behaviors of magnetic abrasive particles. To achieve this objective, a multiscale numerical algorithm was developed, coupling discrete particle dynamics with magnetic forces for analyzing the migration, agglomeration, and rotational movements of magnetic abrasive particles under the combined effect of a magnetic field and workpiece surface. Existing models often neglect the magnetization forces acting between particles, which results in an incomplete representation of particle motion and behavior. To overcome these limitations, a novel adhesive discrete element dynamics model was established utilizing Hertz-Mindlin contact theory for incorporating both inter-particle and magnetic forces. This model accounts for essential microscale processes, which includes the displacement and rotation of magnetic particles within a dynamic magnetic field. In addition, it considers the complex magnetic field interactions between abrasive particles, capturing the way they affect each other to agglomerate to form magnetic particle brushes because they experience magnetic forces throughout the MAF process. The robustness of the model was further enhanced through simulations that recreated the magnetization phenomena of magnetic abrasive particles and analyzed their motion patterns under varying speeds and displacement conditions on a flat processing surface. This analysis enabled identifying critical particle behavior, which includes forming cluster-like aggregates because of magnetization effects. The study utilized particle classification methods common to dense granular flows, which enabled a thorough categorization of particle types based on their specific movements and roles within the finishing process. This classification facilitated a more detailed examination of each category’s contributions, from active particles involved in shear flow to those in quasi-static states that minimally impact the finishing quality. Subsequently, experimental studies were conducted to evaluate the effects of different machining gaps and magnetic pole rotational speeds on particle motion across various locations within the finishing zone. The experimental results indicate that the turnover renewal and movement frequency of the magnetic particles in cluster-like aggregates can be improved by increasing the rotation speed of the magnetic pole and decreasing the machining distance to improve the grinding efficiency of the magnetic particles for the planar workpiece. The experimental data showed a high degree of consistency with the simulation results, particularly in terms of particle clustering patterns and rotational dynamics influenced by magnetic forces. The model accurately predicted the clustering behavior of particles resulting from magnetization and the effect of the magnetic field on particle dynamics within the MAF process. The close alignment between simulated and experimental findings highlights the predictive accuracy of the model and effectiveness in capturing key particle behaviors within magnetic fields. This study presents a comprehensive approach for modeling the behavior of magnetic abrasive particles in MAF processes, addressing key limitations of previous models by integrating both magnetic and mechanical interactions through an adhesive discrete element dynamics model. The model successfully captures the effects of magnetization on particle clustering and motion, which provides a realistic simulation framework that reflects the actual dynamics observed during experimental validations. The results confirm that this model can accurately predict particle motion, agglomeration, and clustering, which are critical for optimizing MAF efficiency and quality. This model offers significant potential for future studies to enhance magnetic abrasive finishing techniques by establishing a robust theoretical foundation and experimental basis, particularly in the precision manufacturing of complex workpieces.
  • Effect of Conditioning Slurry on Material Removal Stability in Fixed- abrasive Chemical Mechanical Polishing of Single-crystal SiC
    WU Pengfei, LIU Ning, HE Lei, ZHU Nannan, ZHU Yongwei
    China Surface Engineering. 2025, 38(5): 301-311. https://doi.org/10.11933/j.issn.1007-9289.20240417002
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    Single-crystal SiC is a third-generation semiconductor material distinguished by its wide bandgap, high electric-field breakdown strength, excellent thermal conductivity, and low thermal expansion coefficient. These properties make it ideal for applications in new-energy vehicles, smart home systems, ultra-fast charging technologies, and satellite communications. Single-crystal SiC is an exceptionally hard material with a Mohs hardness close to 9.5, which is second only to that of diamond. Its high chemical inertness in many common chemical environments makes single-crystal SiC more challenging to process during chemical-mechanical polishing (CMP) than other materials. When fixed abrasive pads are used to polish single-crystal SiC, fine debris accumulates and limits wear and dressing effects on the pad substrate, delaying the exposure of fresh diamond abrasives. This delay leads to low material removal rates (MRR) and unstable material removal rate variation (MRRV) during polishing. Adding abrasives to the polishing slurry accelerates substrate wear through interactions with the workpiece, thereby exposing diamond grains more rapidly and enhancing the MRR. The strong oxidizing agents of the slurry may react with these abrasives over time, diminishing the pad’s dressing capability and consuming oxidizers, which further weakens the chemical oxidation of the workpiece surface. To address low polishing efficiency and unstable MRR in the CMP of single-crystal SiC, this study introduces an efficient CMP method for single-crystal SiC based on online conditioning for fixed-abrasive pads. Self-developed agglomerated diamond (AD) particles were employed as abrasives to prepare fixed-abrasive pads, and conditioned them in situ with a specialized slurry employing the Taguchi method. We systematically varied the primary particle size of the AD, polishing pressure, abrasive concentration in the conditioning slurry, and H2O2 concentration to assess their effects on MRR, surface roughness, friction factor, and surface morphology of the fixed abrasive pad. Orthogonal experiments revealed that a primary particle size of AD abrasive is 7-10 μm, the polishing pressure is 27.6 kPa, H2O2 concentration is 10%, and the abrasive concentration in the conditioning slurry is 3%, resulting a maximum MRR of 27.3 μm / h. Furthermore, it was found that the online conditioning capability of the fixed abrasive pad is influenced by the abrasive particle size and type in the conditioning slurry. Silicon carbide powder with a particle size of 8 000 mesh has better dressing ability than alumina powder, and larger abrasive particles in the slurry enhanced pad conditioning. In addition, the impact of different conditioning slurry types on the friction factor during the polishing process varied under identical polishing pressures, and the friction factor was positively correlated with the MRR. The erosive effects of the conditioning slurry and the micro-fracturing of the AD abrasives both contribute to the self-conditioning process of the fixed abrasive pad, which enhances the stability of material removal during the CMP process, thereby facilitating the efficient polishing of single-crystal SiC. This development lays the foundation for industrial-scale polishing of single-crystal SiC using fixed-aggregated diamond abrasive pads.
  • Effects of HiPIMS Frequency on the Microstructure and Properties of TiZrN / TiN Nano-multilayer Film Deposited by a Hybrid Deposition Technique Combining AIP and HiPIMS
    WEI Yongqiang, ZHANG Xiaoxiao, ZHANG Huasen, GU Yanyang, YANG Jiale, JIANG Zhiqiang, WEI Chunbei, ZHONG Sujuan
    China Surface Engineering. 2025, 38(5): 312-325. https://doi.org/10.11933/j.issn.1007-9289.20240326005
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    With the advancement of modern manufacturing industries, the failures of many types of equipment are often caused by surface damage to critical components. These critical components materials performances are significantly enhanced by surface modification methods. Arc ion plating and high power impulse magnetron sputtering are two highly effective physical vapor deposition techniques, which are used widely to deposit advanced thin-film architectures, including monolayers, nano-multilayers, superlattices, gradient structures, and multi-element films. In particular, nano-multilayer films have demonstrated significant improvements in hardness and wear resistance. Adjusting the architecture of these films—specifically the layers amount and monolayer thickness —has proven to be an effective strategy for improving their properties. This study focused on the fabrication of TiZrN / TiN nano-multilayer films using a hybrid deposition technique combining AIP and HiPIMS. The TiZrN / TiN nano-multilayer films were deposited on M2 high-speed steel substrates and silicon wafers at various HiPIMS frequencies to investigate the influence of deposition parameters on the microstructure and properties of the TiZrN / TiN nano-multilayer films. The objective was to optimize the deposition process and enhance the mechanical and tribological performances of the films for future applications. The surface morphology, elemental composition, phase structure, and mechanical properties of the TiZrN / TiN nano-multilayer films were characterized by scanning electron microscopy (SEM), energy-dispersive spectroscopy (EDS), X-ray diffraction (XRD), Rockwell hardness tests and nano-indentation tests. Tribological and corrosion resistance properties were assessed by ball-on-disk tribometer and CHI660E electrochemical workstation respectively. Potentiodynamic polarization curves were used to evaluate the self-corrosion potential and current density of the samples in a 3.5wt.% NaCl solution. An increase in HiPIMS frequency improved the surface quality of the films and reduced macroparticles formation. However, the competition between ion attraction to the substrate and high-energy ion bombardment affected the film deposition rate. As the HiPIMS frequency increased, the film thickness first increased and then decreased. The maximum thickness of 533.71 nm was observed at 600 Hz, while the minimum thickness of 488.26 nm occurred at 1 000 Hz. At 600 Hz, the films exhibited a minimum grain size of 4.01 nm, with corresponding hardness and elastic modulus values of 30.5 GPa and 290.67 GPa, respectively. At 800 Hz, the Zr / (Ti+Zr) ratio reached a peak of 25%, grain size increased slightly to 4.23 nm, and the hardness and elastic modulus reached maximum values of 46.28 GPa and 356.31 GPa—over five times greater than those of the M2 high-speed steel substrate. The wear rate at this frequency reached a minimum of 1.46×10-8 mm3·N-1·mm-1, demonstrating excellent wear resistance compared to the substrate. At 1 000 Hz, the Zr / (Ti+Zr) ratio dropped to a minimum of 22%, and the average grain size increased to 5.31 nm. meanwhile the films exhibited the best corrosion resistance, with a maximum self-corrosion potential of -0.39 V (vs. SCE) and a minimum self-corrosion current density of 0.731 μA / cm2. Compared to the M2 high-speed steel substrate, the self-corrosion potential increased by approximately 0.454-0.583 V, while the self-corrosion current density decreased by approximately 7.440-8.914 μA / cm2. All TiZrN / TiN nano-multilayer films deposited under different HiPIMS frequencies exhibited preferred (220) orientations, with average grain sizes ranging from 4.01 to 5.31 nm. The hardness of all films exceeded 30 GPa. Compared to the M2 high-speed steel substrate, the TiZrN / TiN nano-multilayer films showed significant improvements in hardness, wear resistance, and corrosion resistance. The nano-multilayer structure played a crucial role in determining the microstructure and performance of the films. These findings provide an experimental basis and technical guidance for optimizing the deposition processes of hard films. This hybrid method shows promising potential for practical applications in high-performance surface protection.
  • Preparation and Tribocorrosion Properties of a Thermal Treatment- anodized Composite Carbon Fiber Coating on the Surface of a TC4 Titanium Alloy
    PEI Wenle, XIE Zhuangzhuang, PEI Xiaoliang, WANG Jianmei
    China Surface Engineering. 2025, 38(5): 326-333. https://doi.org/10.11933/j.issn.1007-9289.20240717001
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    TC4 titanium alloys are extensively used in marine engineering owing to their exceptional strength, light weight, and excellent corrosion resistance. However, the high-salinity, high-humidity corrosion environment and long-term mechanical wear significantly accelerate the tribocorrosion of TC4. This process leads to the destruction and shortened lives of marine engineering components. Therefore, there is an urgent need to develop an effective technology to enhance the anti-corrosion and wear resistance of marine equipment in harsh marine environments. The aim of this study is to enhance the tribocorrosion properties of a TC4 titanium alloy by developing a thermal treatment-anodized composite carbon fiber coating (TAD-CF). This method combines anodization, spraying, and coating techniques to form a strong protective layer that effectively reduces wear and corrosion. Specifically, the TC4 titanium alloy was anodized in a glycol electrolyte at 60 V for 20 min to obtain a nanoparticle porous titanium dioxide (TiO2) layer and then heat-treated for 3 h to improve its structural integrity and protective properties. Subsequently, the substrate surface was coated with a uniform ceramic adhesive layer and then with carbon fiber, which firmly adhered after curing. The integration of carbon fibers into the coating is expected to provide additional mechanical strength and improve the wear resistance of the coating. Furthermore, comprehensive analyses of the surface morphology and elemental distribution of TAD-CF were conducted using scanning electron microscopy (SEM) and confirmed the successful formation and uniform distribution of the coating. These results indicate the successful formation of the nanoporous TiO2 coating under the specified anodic oxidation conditions. To evaluate the performance of the TAD-CF coating, a multifunctional fretting corrosion tester was employed to assess its corrosion resistance and tribological properties in air and simulated marine environments. Electrochemical corrosion tests demonstrated that the self-corrosion potential of TAD increased significantly and that the corrosion current density decreased significantly, with a measured value of 65.2 nA / cm2. Concurrently, the polarization resistance increased to 0.743 GΩ, indicating that the corrosion resistance of TAD is greatly enhanced, compared with that of TC4. Under static corrosion conditions, the corrosion current density of the TAD-CF samples decreased to 8.57 nA / cm2, whereas the polarization resistance increased to 9.08 GΩ, further confirming its excellent corrosion protection. Friction and wear tests revealed that the average coefficient factor for the TAD-CF samples was significantly lower than those of the untreated TC4 samples, which proves that the TAD-CF coating significantly improves the tribological properties of TC4 in a marine environment. In conclusion, TAD-CF exhibited remarkable corrosion and abrasion resistance, thereby indicating its broad application prospects in marine corrosion protection. Furthermore, this study not only demonstrates the potential of TAD-CF coatings to improve the durability of marine engineering components but also provides important insights into the development of advanced protective coatings that can address a variety of challenges. However, it must be recognized that sliding friction can cause damage to the coating structures of TAD and TAD-CF samples, which potentially weakens their long-term protective effect. Future research should focus on resolving the influence of sliding friction on the integrity of the coating to optimize its protective properties.
  • Effects of C Target Power on Microstructure, Mechanical Properties and Tribological Properties of AlCrTiCN Coatings
    CHEN Haoran, FAN Qixiang, GUO Minglu, WU Zhenghuan, HAO Xuehui, WANG Tiegang, LIU Yanmei, CAO Fengting
    China Surface Engineering. 2025, 38(5): 334-346. https://doi.org/10.11933/j.issn.1007-9289.20240326002
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    Three AlCrTiCN coatings, varying in carbon content, were fabricated on single-crystal silicon wafers and stainless-steel substrates by adjusting the C target power to 0, 50, and 100 W. The Al60Cr20Ti20 and C targets were connected to a direct-current pulse and radio-frequency magnetron sputtering power, respectively. The microstructures, chemical compositions, and mechanical and tribological properties of the coatings were characterized using X-ray diffractometry, field-emission scanning electron microscopy, X-ray photoelectron spectroscopy, and nanoindentation. The primary phase of the coatings was the NaCl-type fcc-(Al,Cr,Ti)(C,N) phase. For the coating fabricated using a C target power of 50 W, the hcp-C3N4 phase was detected. However, upon further increasing the C target power to 100 W, the hcp-C3N4 phase disappeared, and no diffraction peaks corresponding to C or its compounds were detected. This observation may be attributed to the fact that a proportion of the C atoms is dissolved in the (Al,Cr,Ti)N crystal, while another portion is in an amorphous state. All the three coatings grew preferentially along the (111) crystal plane. As the C target power increased, the diffraction peaks broadened and the (111) texture coefficient decreased. The grain size also decreased, which might have been due to the increased amount of amorphous C, which hindered grain growth. The surface quality of the coatings improved with increasing C target power. The hardness of the coatings increased gradually from 10 GPa to 23.7 GPa, owing both to the solid solution effect of the C element and the reduced grain size, which lengthens the grain boundaries and hinders the movement of the dislocation. The H / E*, H3 / E*2 and We values also increased with increasing C target power and reached their largest values at C target power of 100 W. The adhesion strength first increased from 38.2 N at the C target power of 0 W to 43 N at the C target power of 50 W, subsequently decreasing slightly to 41.7 N at the C target power of 100 W. The adhesion strength first increased, probably because of the formation of a nanocomposite structure consisting of fcc-(Al,Cr,Ti)(C,N) and amorphous C, which prevented the generation and propagation of cracks at the interface between the substrate and coating. However, it decreased afterwards, which might be ascribed to the high internal stress generated by the growing amorphous C. With an increase in the C sputtering power, the friction factor first increased from 0.57 to 0.79, and then it decreased to 0.55. Unexpectedly, the friction factor did not drop with the C target power. This may be because the C3N4 phase formed in the coating with a C target power of 50 W deteriorated the lubrication effect of the graphite phase (sp2). Nevertheless, a significant drop in the wear rate was noted with the addition of C, and the coating fabricated using a C target power of 100 W exhibited the lowest wear rate (about 8.19×10-6 mm3·N-1·m-1). This improvement can be ascribed to the enhanced mechanical properties associated with coatings fabricated using a higher C target power. Notably, the wear mechanisms of the three coatings differed. The coating fabricated using a C target power of 0 W failed primarily because of wear caused by oxidation, abrasion, and adhesion. The failure mechanism of the coating fabricated using a C target power of 50 W was primarily abrasive wear. As the C target power increased to 100 W, the coating was found to lose efficacy predominantly owing to adhesion wear because large amounts of lumps rich in Fe are found in the wear track. This study indicates that the addition of C to AlCrTiN coatings could improve their mechanical and tribological properties, and that these enhanced coatings could potentially find application in the fabrication of cutting tools.
  • Preparation and Performance Characterization of (Ni@SiC)p Composite Absorbing Materials
    SU Hui, ZHENG Qi, YAN Feng, SUN Xiangdong, XING Zhonghui, CHEN Yujin, CAO Maosheng
    China Surface Engineering. 2025, 38(5): 347-355. https://doi.org/10.11933/j.issn.1007-9289.20240916002
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    With the continual advancements in technology, increasingly intense electronic and information warfare, electromagnetic radiation, and electromagnetic interference have become key factors that affect military operations. Composite absorbing materials are considered an important method to deal with electromagnetic interference as well as an effective means to enhance national military defense capabilities and combat effectiveness. (SiC)p is a semiconductor material with excellent performance, low cost, oxidation and corrosion resistance, and high strength. Its resistivity ranges from 10-2 to 106 Ω·cm and can be continuously adjusted with the manufacturing process, making it a preferred choice for composite absorbing materials. However, the microwave absorption efficiency of (SiC)p has not yet met the requirements for wide bandwidth and strong absorption, and the poor wettability between the material and substrate owing to different chemical bonds significantly affects its application range. Silicon carbide / nickel core-shell structured composite particles, abbreviated as (Ni@SiC)p, were prepared to improve the electromagnetic properties of SiC further and prepare composite absorbing materials with excellent carbide. To investigate the performance, a simple, controllable, rapid, and high-precision chemical deposition technique was used to modify the surface of the Si. The experimental process included preprocessing of (SiC)p and its surface chemical deposition. The preprocessing introduced catalytically active sites, including oxidation etching, hydrophilic treatment, sensitization, and the activation of (SiC)p. The pretreated (SiC)p was then added to the chemical deposition solution for surface modification with a deposition time of 1-2 h. Scanning electron microscopy, energy dispersive spectroscopy (EDS), and X-ray diffraction (XRD) were used to characterize the morphology, composition, and phase of the samples before and after modification, and a vector network analyzer was used to measure the electromagnetic absorption properties of SiC before and after modification. The results showed that (SiC)p is light gray before modification and turns black after modification, indicating substantial changes on the SiC surface. The micromorphology revealed that the surface of (SiC)p is smooth before modification, with a small amount of broken powder adhering because of processing. After modification, the particle surface is no longer smooth, with new substances deposited and no smooth (SiC)p exposed. The EDS showed that before modification, there are obvious Si peaks and a certain amount of C and O peaks; after modification, new Ni and P peaks appear, indicating that the newly deposited substances are Ni and P. EDS mapping of the modified SiC revealed the presence of Si, Ni, P, C, and O elements uniformly distributed in the surface deposition layer of the SiC, further indicating that the new substance deposited on the surface is Ni. The XRD results showed that the (SiC)p used in the experiment was α-(SiC)p, with only SiC diffraction peaks (SiC PDF#29-1131) observed before modification. After modification, obvious Ni diffraction peaks (Ni PDF#04-0850) are visible, and the diffraction peaks show a broad peak, indicating that the Ni particles on the surface of the modified SiC are amorphous, with fine sizes, forming ultra-fine Ni powder. A comparison of the electromagnetic properties before and after modification revealed a significant improvement in the absorption performance after modification, with the real part of the dielectric constant increasing by 3 to 6 times and the imaginary part by 2 to 7 times; the electromagnetic loss increases by 2 to 4 times and the dielectric loss increases by 3 to 5 times. At a frequency of 11.6 GHz, the reflection loss (RL) of (Ni@SiC)p is -41.25 dB, with an effective bandwidth of 7.28 GHz. Finally, a detailed analysis of the electromagnetic enhancement mechanism of (Ni@SiC)p was conducted. From a microscopic perspective, the composite structural unit endows each (Ni@SiC)p with the dual attributes of electrical and magnetic loss. From a macroscopic perspective, the absorbing performance of the new material is significantly enhanced, which is more conducive to achieving the goals of lightweight, thin, wideband, and high-strength absorbing materials. This work provides new methods and ideas for exploring and researching the preparation of absorbing materials in the national defense field that are simple to operate, well controlled, inexpensive, and suitable for large-scale promotion.
  • Corrosion Inhibition of Carbon-steel Surfaces in Acidic Media Using a Compound of Betaine Hydrazide Chloride and KI
    LIU Yuelong, LIU Jinyan, CHEN Bo, REN Xiaohui
    China Surface Engineering. 2025, 38(5): 356-369. https://doi.org/10.11933/j.issn.1007-9289.20240912001
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    Many industrial production processes involve various inorganic and organic acids and corrosive ions. When appropriate precautionary measures are not employed, the passivation film that forms on the surface of the metal is very fragile and easily damaged, thereby leading to corrosion and resulting in significant economic losses and safety hazards. Therefore, in certain industrial environments, adopting measures to enhance the corrosion resistance of the metal is necessary. Corrosion inhibitors are widely used in metal protection, especially for carbon steel. Adding a corrosion inhibitor can not only enhance its anti-corrosion performance without compromising the overall structure of the metal but also can extend the life and durability of metal structures and equipment. Further, green corrosion inhibitors can meet the requirements of low carbon, eco-friendly, and biodegradation, which is consistent with the concept of green chemistry. Betaine organic, with atoms of N, S, O, and aromatic rings, can adsorb on metal surfaces to prevent corrosion. Thus, this paper investigated the corrosion protection effects of betaine hydrazide chloride and KI as inhibitors for carbon steel in a hydrochloric acid medium. Q235 steel specimens were prepared by laser cutting into two sizes: 20 mm×30 mm×3 mm and 10 mm×10 mm×3 mm. The surfaces of the specimens were sanded with graded sandpaper and cleaned with ethanol and acetone in preparation for testing. The samples were immersed in 1 mol·L-1 hydrochloric acid solution at 30 ℃ for 24 h without or with different concentrations of corrosion inhibitor solutions. The weightlessness method experiment showed that a single corrosion inhibitor, GRT, achieved a corrosion inhibition efficiency of 44.87% at a concentration of 4.0×10-3 mol·L-1. GRT was compounded with KI to enhance the corrosion inhibition efficiency further and reduce dosage. With the addition of KI, the corrosion inhibition efficiency increased accordingly. When the concentration of I- increased to 2.0×10-3 mol·L-1, the corrosion inhibition effect was the best, and the corrosion inhibition efficiency reached 94.86%. Electrochemical measurements were conducted using kinetic potentiodynamic polarization with potential variations ranging from -150 to 150 mV in the HCl system. In addition, impedance spectroscopy was performed with open-circuit potential scanning frequencies ranging from 0.01 to 105 Hz and AC amplitude fluctuations of 10 mV. A significant increase in the electrical resistance of the carbon steel surface was observed, which indicates that the corrosion inhibitor effectively protects the carbon steel from corrosion. Analysis of the polarization curves suggests that the compounded corrosion inhibitor is a cathodic-dominant hybrid corrosion inhibitor. Surface analysis using atomic force microscopy (AFM) and X-ray photoelectron spectroscopy (XPS) showed that the corrosion inhibitor smoothed the carbon steel surface, enhancing its corrosion resistance. Quantitative chemistry calculations reveal the accepted and donated electron groups of the corrosion inhibitor. Monte Carlo simulations indicate the stronger adsorption energy for iodine ions compared to that for chlorine ions. Molecular dynamics simulations demonstrate that corrosion inhibitor molecules can adsorb parallelly on the Fe {110} surface, with an adsorption energy of -423.722 kJ·mol-1. These simulation results align with experimental findings, confirming that the compound of GRT and KI serves as an effective corrosion inhibitor. A non-toxic and non-polluting green material GRT was used as a corrosion inhibitor in this paper and the concentration of single GRT was successfully reduced by compounding it with KI. The GRT / KI compound corrosion inhibitor formed a protective film on the surface of the carbon steel, isolating it from the corrosive medium. This greatly reduces the corrosive effect of hydrochloric acid on carbon steel. This study result not only enriched the theoretical foundation of the related field, but also provided the thought inspiration and technical path for the future development of more efficient green corrosion inhibitors.
  • Comparison of the Lubricating Performance of Groove Texture under Gas / liquid Medium Conditions
    SUN Yamin, YANG Huiya, ZHU Tianyu, ZHENG Wei, LÜ Tian, WANG Jingqiu, WANG Xiaolei
    China Surface Engineering. 2025, 38(5): 370-379. https://doi.org/10.11933/j.issn.1007-9289.20240904002
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    The Stirling engine employs an external combustion system that uses pure gas as the working medium in the cylinder chamber, therefore, friction and wear between the piston ring and cylinder liner under gas lubrication remain problems that limit its efficiency and life. It is well known that the cross-hatching pattern created using the honing process is a successful surface texture for oil-lubricated internal combustion engines, however, to the best of our knowledge, research on using honing patterns for the Stirling engines remains lacking. Compared to oil lubrication, the gas medium has a lower viscosity and is compressible. Additionally, the piston rings of the Stirling engine are made of a soft PTFE-based material, which can undergo significant deformation during operation. A model with idealized honing groove on the cylinder liner of the Stirling engine was specifically constructed to verify whether honing patterns can be used to enhance aerodynamic lubrication in the gas environment for decreasing the friction and wear between the piston ring and cylinder liner. The developed model contains the ideal geometric parameters of the honing groove, including width, depth, pitch, and crossing angle, as well as several condition parameters, such as speed and ambient pressure. The incompressible and compressible Reynolds equations were solved using the rigid boundary condition or coupling the elastic deformation equation to obtain the hydrodynamic and aerodynamic pressures of the liquid and gas with / without considering the deformation. This enabled comparing the performances of the idealized honing groove with gas or oil lubrication. Finally, the difference between gas and oil lubrication was analyzed to realize a better surface texture design for the Stirling engine. It is found that the elastic deformation of the PTFE material caused by hydrodynamic pressure in the liquid lubrication condition had the same order of magnitude as the film thickness, which resulted in a significant decrease in hydrodynamic pressure. The elastic deformation caused by aerodynamic pressure was considerably smaller than the film thickness, therefore, the elastic deformation can be ignored while using gas lubrication. For the effect of sliding speed, the results indicate that under rigid boundary conditions, the load-bearing capacity of the liquid film increased linearly with speed, while under elastic boundary conditions, it increased with a convex function of speed. The load-bearing capacity of the gas film increased as a concave function of speed, indicating that the load-bearing capacity of the gas film was enhanced at high speed. The optimal parameters for the grooves in liquid lubrication and gas lubrication were also different. The optimal ratio of the groove width over pitch for the rigid boundary in liquid lubrication was 0.5-0.65, and for the elastic boundary, it was 0.4-0.55. The optimal ratio of the groove width over pitch under the gas lubrication condition was 0.3-0.4, which is obviously lower than that of liquid lubrication. This indicates that the groove texture should be sparser in the gas lubrication condition. The above results demonstrate that honing texture can be used to improve the friction and wear performances between the cylinder and piston rings of Stirling engine; however, its design parameters should be different from the liquid lubrication conditions.
  • Development of Ultra-low-pressure Plasma Spray Equipment
    WU Chaofeng, WANG Bo, LIANG Zhimin, NI Liyong, WANG Dianlong
    China Surface Engineering. 2025, 38(5): 380-386. https://doi.org/10.11933/j.issn.1007-9289.20241004001
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    Ultra-low-pressure plasma spraying (ULPPS) is a critical enabling technology for developing advanced aero-engines that can achieve high-quality coating with customized design across scales and efficient non-line-of-sight deposition, and it is widely recognized as the ideal fabrication method for high-performance thermal barrier coatings (TBCs) in advanced aero-engines. The coatings produced exhibit high deposition efficiency, dense structure, controllable microstructure, high thermal strain tolerance, and strong adhesion to the substrate. China’s entry into the field of technologies such as PS-PVD has been relatively recent, with research focused on spraying processes, and equipment development heavily constrained by foreign technologies. A novel ULPPS system has been domestically developed, addressing the urgent need for import substitution in advanced thermal barrier coatings (TBCs) manufacturing. This innovation specifically targets the critical requirements of China’s aerospace sector for high-performance turbine blade protection with enhanced deposition efficiency. Research has been conducted to solve core technical issues of traditional and existing PS-PVD spraying power supplies, such as low effective output power, large output current ripple, and poor dynamic adaptability and stability of the arc. A two-stage structure of “rectification + chopping voltage reduction” has been adopted based on the high-frequency chopping main circuit topology scheme and multiphase interleaved parallel technology to achieve low ripple, high power, high stability, and high dynamic response characteristics of voltage and current output control. Based on the active modulation technology scheme of the power supply, a fully digital control strategy for high-frequency chopping power supply has been developed using methods such as high-frequency sampling digitization of input signals, control strategy discretization digitization, control output digitization, and communication digitization to enhance the response speed, dynamic applicability, and output stability of the power supply from the bottom-level control logic. A steady-state and dynamic mathematical model of the high-frequency chopping power supply has been established, and a low ripple intelligent control algorithm based on the single neural network has been developed for reducing the output current ripple and enhancing the stability of the plasma arc. The laws of arc changes throughout the spraying process and corresponding changes in equivalent load impedance have been analyzed. A mathematical model and mapping relationship of the spraying state and equivalent impedance change patterns have been established, thereby developing a dynamic adaptation strategy for the plasma arc that predicts the spraying state and equivalent impedance in real-time, which enhances the stability of the spraying process. The performance of the spraying power supply has been verified and optimized, and a related vacuum system and auxiliary systems have been developed for achieving PS-PVD functionality. A diversified intelligent collaboration and highly integrated automated monitoring and control system for the entire spraying process has been developed for addressing the complex control issues involving multiple variables, parameters, and systems in PS-PVD equipment and spraying processes. The online monitoring of the entire process of spraying processing quality is achieved by collecting, storing, and analyzing process parameters and working state information such as voltage, current, gas flow, and powder feeding speed during the spraying process, and data support is provided for the quality traceability of spraying product production. A graphical human machine interaction interface based on PC terminals was developed to improve the level of visualization and system integration, reducing operational complexity. Yttria-stabilized zirconia (YSZ) ceramic materials, which have been validated for the feasibility and applicability of spraying processes, have been used for sample spraying tests to process efficiency. The tests proved that the vacuum system can achieve closed-loop pressure control in a wide pressure range of 3-80 kPa and 50-1 000 Pa, with an ultimate vacuum degree less than 10 Pa. The power supply rated current can reach 3 000 A, with a spraying power exceeding 120 kW, which is adaptable to different working conditions of 100 V / 1 200 A and 250 V / 480 A. The system can perform low-pressure plasma spraying (3-80 kPa) and ULPPS (50-1 000 Pa) within a wide pressure range from 50 Pa to 80 kPa and achieve plasma physical vapor deposition functions. After the verification of the spraying process, tests of low-pressure spraying operation for 1 h and ULPPS operation for 2 h have been completed, proving that the equipment is safe, reliable, and stable, meeting user specifications, and put to use. The domestic equipment reached the technical indicators of new products from foreign monopolistic enterprises, solving the domestic substitution problem of PS-PVD equipment, ensuring the autonomy, controllability, and security of China’s related industry chains and supply chains. Thus, it is of great significance for China to establish a strategic backup of key national defense technologies.
  • Visual In-situ Measurement of V-shaped Superabrasive Grinding Wheels During Laser Dressing
    DENG Hui, LIU Chaoqiang, GAO Shurong, ZHOU Enhuai, YUCHI Guangzhi, HE Chuan
    China Surface Engineering. 2025, 38(5): 387-397. https://doi.org/10.11933/j.issn.1007-9289.20240619001
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    During grinding or mechanical / electrical dressing, coolants, dielectrics, and oil mist significantly interfere with the visual measurement system, which limits the application of this technology in grinding-wheel measurement, thus resulting in few reports related to the visual measurement of grinding-wheel surfaces. Laser dressing is regarded as the most widely applicable and environmentally friendly technology. It offers the advantages of noncontact and high controllability, and is particularly suitable for dressing superabrasive grinding wheels with complex contours. When performing laser dressing on grinding wheels, no liquid medium is required, and only a trace amount of fine dust is generated (dust removal can be achieved via exhaustion), thus providing a favorable operating environment for the visual measurement system. Hence, the visual measurement method of a V-shaped superabrasive grinding wheel during laser dressing is investigated to achieve rapid on-site measurements of grinding-wheel surface parameters, such as runout error, tip arc error, and laser incident angle. A visual measurement platform for laser dressing is constructed, which comprises a nanosecond fiber laser, a laser galvanometer, an electric spindle, an X-Y manual platform, a Z-axis electric platform, a camera, a light source, and other equipment to realize in-situ continuous acquisition of axial sectional images of various superabrasive profile grinding wheels, including V-shaped grinding wheels, during the dressing process. The peak signal-to-noise ratio (PSNR) is used to compare and evaluate the filtering effects of the median, mean, and Gaussian and bilateral algorithms on the grinding-wheel image. The result shows that their PSNR values are 42.651 6, 37.003 1, 50.136 4, and 72.075 5, respectively. The bilateral filtering algorithm demonstrates the best processing effect on the grinding-wheel images. The edge-detection effects of five commonly used algorithms, i.e., Sobel, Prewitt, Laplacian, Robert, and Canny, are compared. The result shows that the latter offers the most balanced performance in terms of detection accuracy, efficiency, and number of detection points; however, it cannot accurately identify grain features and identifies excessive image edges. By using bilateral filtering, performing 3×3 Sobel gradient calculations, and adopting the OTSU threshold method, the three modules of Gaussian filtering, 2×2 Sobel gradient calculation, and double threshold edge detection in the classical Canny algorithm are improved, thus enabling pixel-level coarse positioning to be achieved at the edge of the axial sectional image of the grinding wheel. Hence, a subpixel edge-detection method based on the improved Canny algorithm and Zernike moment (referred herein as the Canny-Zernike moment) is proposed to achieve accurate subpixel positioning of the edge of the grinding-wheel image. Comparison results show that both the improved Canny algorithm and the Canny-Zernike moment algorithm can completely extract the edge of the axial sectional image of the grinding wheel; however, the image-processing speed of the Canny-Zernike moment algorithm is higher than that of the Canny algorithm. The Canny-Zernike moment algorithm is used to extract the axial sectional contours of the grinding wheel under different laser-beam feed times. Results show that the axial sectional contour line changed from a straight line to a trapezoid, and finally to a V shape. The calculation methods for the V-shaped grinding-wheel surface parameters, such as the circular runout error, total runout error, straightness error, tip arc error, and laser incident angle, are established, and the corresponding MATLAB calculation programs are written. Based on a test, the visual measurements of runout error, straightness and tip arc errors, and laser incident angle require approximately 7.0, 5.4, and 3.7 s, respectively, which satisfy the speed requirements of laser-dressing process monitoring for measuring grinding-wheel surface parameters. The results of this study will accelerate the development of laser dressing and surface-measurement technology for superabrasive profile grinding wheels toward automation and intelligence.
  • Preparation and Corrosion Resistance of Waterborne Zn-Al Coating on the Surface of Sherardized Coating
    ZHANG Tao, WANG Shengmin, LIANG Wei, HUANG Zhiquan, HUANG Teng
    China Surface Engineering. 2025, 38(5): 398-409. https://doi.org/10.11933/j.issn.1007-9289.20240129004
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    The waterborne Zn-Al coating has excellent corrosion resistance and weather resistance, is relatively inexpensive, easy to coat, and is suitable for all types of workpieces and application environments. The application range of sherardized parts is extremely wide, and it is widely used in bridges, railways, and oceans, whereas the sherardized coating has poor corrosion resistance in harsh environments and cannot meet the requirements of use, limiting the continued development of society to a certain extent. In this study, waterborne Zn-Al coating was prepared on the surface of sherardized coating by spraying Zn powder, Al powder, and additives as raw materials to improve the corrosion resistance of sherardized coating. The surface, cross-sectional morphology, and composition of the waterborne Zn-Al coating were characterized using scanning electron microscopy (SEM) with an EDS spectrometer. The electrochemical behavior of the waterborne Zn-Al coating in a 3.5% NaCl solution was characterized by open-circuit potential (OCP), polarization curve (Tafel), and electrochemical impedance (EIS) analyses. The corrosion resistance of the waterborne Zn-Al coating was analyzed using a neutral salt spray test. The results show that the waterborne Zn-Al coating is a composite coating of a phosphate layer and flake Zn and Al powders, primarily composed of Al, Zn, P, Cr, and Fe. The waterborne Zn-Al coating has a dense structure with no cracks, and flake Zn and Al powders are stacked in the phosphate layer. When the surface of the sherardized coating is coated with waterborne Zn-Al coating, the OCP value of the surface is positive, and the sensitivity to electrochemical corrosion is lower. Compared with the sherardized coating, the self-corrosion potential of the waterborne Zn-Al coating has a positive shift of 72 mV, the self-corrosion current density of the waterborne Zn-Al coating is 1.242×10-5 A·cm-2, which is only about 7.9% of the sherardized coating, and the polarization resistance is 12.5 times of the sherardized coating. The impedance arc radius of the waterborne Zn-Al coating is much larger than that of the sherardized coating, indicating that the waterborne Zn-Al coating has a better inhibitory effect on charge transfer. After 48 h of the neutral salt spray test, the surface of the sherardized coating was covered with white rust; after 144 h of the neutral salt spray test, 50% of the surface of the sherardized coating was covered with red rust, and the protective ability of the red rust area at the edge was lost. After 1 000 h of the neutral salt spray test, white rust was observed on the surface of the waterborne Zn-Al coating. After 2 000 h of the neutral salt spray test, no red rust was detected on the surface of the waterborne Zn-Al coating, demonstrating excellent corrosion resistance. The corrosion products of the waterborne Zn-Al coating were analyzed by XRD. The main components of white rust are Zn6Al2(OH)16CO3·4H2O, Zn5(OH)8Cl2·H2O and Zn4CO3(OH)6·H2O, Zn6Al2(OH)16CO3·4H2O with dense structure, good adhesion, and stable properties. It has a certain protective effect on water-based zinc-aluminum coatings and corrosion products with loose structures and can effectively prevent the corrosion medium from spreading to the inside of the coating. The anti-corrosion mechanism of the waterborne Zn-Al coating is primarily divided into three aspects: physical shielding, electrochemical anti-corrosion, and passivation. The sheet zinc and sheet aluminum powders are stacked and nested in layers, which significantly prolong the erosion path of the corrosive medium. The potentials of the flake Zn and flake Al powders are lower than that of the Fe matrix. In a galvanic cell composed of a corrosive medium, flake Zn powder and flake Al powder first lose electrons and act as anodes to be corroded, protecting the cathode at the expense of the anode. The coating exhibits an obvious passivation zone in electrochemistry, and the phosphate layer works with an oxide layer of zinc and aluminum powder, which can effectively prevent the erosion of the corrosive medium.
  • Friction and Wear Characteristics of Ball Bearings under Current-carrying Conditions
    AN Gezheng, LIANG Xingxin, DONG Xiaowei, LUO Baoyang, LIU Xuru
    China Surface Engineering. 2025, 38(5): 410-419. https://doi.org/10.11933/j.issn.1007-9289.20241009003
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    Bearing current damage is a primary cause of electromechanical equipment failure. When such damage occurs, the release of discharge energy generates localized high temperatures and leads to the ablation of the metallic materials of the bearings and deterioration in the functionality of the lubricants, which significantly affects the service lives of the bearings. In-depth research on the electrical damage mechanisms of rolling bearings under current-carrying friction is currently lacking. In ball bearings, the simultaneous presence of friction and electric current on the same surface results in electrical damage, which is influenced by their combined effects. A coupling relationship exists between rolling friction damage and electrical erosion damage, thus indicating the necessity for a comprehensive study of electrical damage in bearings that integrate both operational conditions and electrical parameters during bearing operation. In this study, 6006ZZ ball bearings were used as test samples, and a current-carrying friction wear test rig was established to simulate various operating conditions of the rolling bearings. Experiments were designed based on parameters such as the electrical breakdown frequency, rotational speed, and lubrication media, focusing on the electrical breakdown characteristics and wear properties under current-carrying friction. This investigation aimed to explore the influence of operating parameters on the electrical insulation performance of rolling bearings. After the experiments, scanning electron microscopy (SEM) was employed to observe the micro-morphology of the bearing raceway surface. Additionally, energy dispersive spectroscopy (EDS) was used to analyze the elemental composition and distribution on the surface after testing, thus providing further insights into the characteristics and mechanisms of electrical damage associated with current-carrying friction. The results showed that the critical breakdown voltage of the ball bearings decreased with an increase in the number of breakdowns but increased with higher rotational speeds. Under the operating conditions of 400 r / min and ISO VG32 oil lubrication, the critical breakdown voltages in the three consecutive current breakdown tests were 1.066, 1.006, and 0.954 V, showing a decreasing trend. When the rotational speed increased from 200 to 800 r / min, the critical breakdown voltage of the bearing increased from 0.706 to 1.083 V, and the system resistance after breakdown increased from 0.44 to 0.51 Ω. The breakdown voltage was related to the viscosity of the lubricating medium. Under grease-lubricated conditions, the bearing was more likely to form a stable lubricating oil film at low speeds, which significantly increased the breakdown voltage at the same speed. Compared with lubricating oil, ball bearings lubricated with grease exhibited significant increases in critical breakdown voltages of 42.3%, 13.1%, and 12.8% at rotational speeds of 200, 400, and 800 r / min, respectively. Current breakdown is a necessary condition for the formation of electrical damage on the surface of bearing raceways. Without breakdown and under pure mechanical rolling friction, the surface damage of the bearing raceways was mainly characterized by scuff marks and abrasive wear. However, after the breakdown, dense, small-arc high-temperature ablation pits appeared on the surfaces of the bearing raceways, and the pit density increased with the applied voltage. Through experimental investigations, this study elucidated the influence of operating parameters on the electrical insulation performance of rolling bearings. Additionally, this study delves into the characteristics of the electrical damage induced by current-carrying friction and conducts a thorough analysis of the mechanisms underlying current-induced damage in bearings. The research findings provide valuable guidance for the safe operation of ball bearings under current-carrying conditions and for the further exploration of protective measures against electrical damage in bearings.
ISSN 1007-9289　CN 11-3905/TG
Supervised by: China Association for Science and Technology
Sponsored by: Chinese Mechanical Engineering Society
Edited and Published by: Editorial Office of China Surface Engineering
Copyright © China Surface Engineering, All Rights Reserved.
Postal Code: 100037　
Tel: (010)88379020/88379056　
E-mail：cse1988@csejournal.com
Visited
Total visitors:　
Visitors of today: 　
Now online:
京ICP备05060958号-16    Powered by Beijing Magtech Co. Ltd,.