| 引用本文: | 管筱竹,郑贺,郭鹏,王振玉,柯培玲,西村一仁,汪爱英.Si/O含量对DLC涂层腐蚀性能的影响[J].中国表面工程,2024,37(6):283~296 |
| GUAN Xiaozhu,ZHENG He,GUO Peng,WANG Zhenyu,KE Peiling,KAZUHITO Nishimura,WANG Aiying.Effect of Si / O Content on the Long-term Corrosion Performance of DLC Coatings[J].China Surface Engineering,2024,37(6):283~296 |
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| Si/O含量对DLC涂层腐蚀性能的影响 |
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管筱竹1，2，郑贺3，郭鹏2，王振玉2，柯培玲2，西村一仁2，汪爱英2
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1.宁波大学材料科学与化学工程学院 宁波 315211 ；2.中国科学院宁波材料技术与工程研究所海洋关键材料重点实验室 宁波 315201 ；3.宁波甬微集团有限公司 宁波 315033
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| 摘要: |
| 类金刚石碳（DLC）涂层兼具耐腐蚀和耐摩擦磨损等优点，是理想的海工装备零部件耐摩擦腐蚀防护材料之一。然而， DLC 涂层在沉积过程中往往会出现大颗粒、针孔等缺陷，且短期腐蚀性能评价难以预测其长时间腐蚀防护性能，因此关键装备的长期可靠服役面临挑战。采用等离子体增强化学气相沉积（PECVD）技术，通过调控乙炔（C2H2）和六甲基二硅氧烷 （HMDSO）流量比，在 17-4PH 基体上实现不同 Si / O 含量掺杂 DLC 涂层的制备，系统研究 Si / O 含量对涂层组分、结构以及在 3.5wt.% NaCl 溶液中短期（2 h）及长期（360 h）腐蚀行为。结果表明：随着 HMDSO 流量增加，涂层中 Si（0at.%~7.6at.%） 和 O（2.21at.%~4.88at.%）元素含量均增加，但不改变涂层非晶结构特征。随着 Si / O 含量增加，涂层 sp2 团簇尺寸降低， sp3 含量上升。短期腐蚀性能测试发现，随着 Si / O 含量增加，涂层的耐腐蚀性能提升，其中 S4 涂层（Si 元素含量为 7.6at.%） 相比 S1 涂层（Si 元素含量为 0at.%）的腐蚀电流密度下降四倍。长时间（360 h）腐蚀测试中原位 EIS 结果也证实，涂层在整个浸泡周期均具有优异的耐腐蚀性，且随 Si / O 含量增加，耐腐蚀性能越优异。然而根据电感耦合等离子体发射光谱仪 （ICP-OES）的结果，所有涂层样品在腐蚀测试后均发现在测试液体中有微量铁离子，涂层和基体界面处存在轻微金属腐蚀。 结合顺磁电子自旋共振波谱（ESR）仪的测试结果，高 Si / O 含量减少了涂层中缺陷结构，提升了整体致密性，且长时间浸泡后增加了涂层的缺陷密度。综上所述，在 DLC 涂层中掺杂 Si / O 元素，可提高涂层的抗腐蚀性能，这为海洋装备表面长期高性能腐蚀防护提供了一种新策略。 |
| 关键词: Si / O-DLC 涂层 腐蚀性能 长期腐蚀 致密性 |
| DOI：10.11933/j.issn.1007-9289.20231228004 |
| 分类号:TG156；TB114 |
| 基金项目:国家重点研发计划（2022YFB3809000）；国家自然科学基金杰出青年基金（52025014）；宁波市重点研发计划（2023Z009，2023Z110） |
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| Effect of Si / O Content on the Long-term Corrosion Performance of DLC Coatings |
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GUAN Xiaozhu1，2，ZHENG He3，GUO Peng2，WANG Zhenyu2，KE Peiling2，KAZUHITO Nishimura2，WANG Aiying2
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1.School of Materials Science and Chemical Engineering, Ningbo University, Ningbo 315211 , China ；2.Key Laboratory of Advanced Marine Materials, Ningbo Institute of Materials Technology and Engineering,Chinese Academy of Sciences, Ningbo 315201 , China ；3.Ningbo Yongwei Group Co., Ltd., Ningbo 315033 , China
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| Abstract: |
| With the rapid development of the ocean economy, an increasing amount of offshore equipment is being used for ocean measurement, observation, and forecasting. However, in the harsh environment of seawater, the key metal parts of many pieces of marine equipment, including manipulators, hydraulic plungers, and ship propeller bearings, face serious corrosion damage that can directly affect the reliability and service life of the equipment. Surface coating technology can protect the key metal parts and thereby extend the service life of the marine equipment without changing the excellent mechanical and processing properties of metal materials. Hence, they have attracted much attention in both academia and industry. Diamond-like coating (DLC) has the advantages of high corrosion resistance and wear resistance. Moreover, it becomes one of the ideal protective coatings for marine equipment components. However, defects such as large particles and pinholes are often introduced during the deposition process of DLC. In addition, it is difficult to predict its long-term corrosion protection performance with the current short-term corrosion research. Here, Si / O co-doped DLC coatings with different Si / O contents were fabricated on 17-4PH substrates by changing the gas flow ratio via plasma-enhanced chemical vapor deposition (PECVD). The effects of the Si / O content on the coating composition, structure, and short-term (2 h) and long-term (360 h) corrosion behavior in a 3.5wt.% NaCl solution were systematically studied. For comparison, 17-4PH stainless steel without a surface treatment was also tested. The surface and cross-sectional morphologies of coated samples were observed via scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Raman spectroscopy, X-ray photoelectron spectroscopy (XPS) and Fourier-transform infrared spectroscopy (FT-IR) were used to characterize the chemical components and bonding structure of the Si / O-DLC coatings with different Si / O contents. The corrosion properties of the bare substrate and coated samples were tested using a Gamry electrochemical workstation. Their long-term corrosion performances were also evaluated. Inductively coupled plasma emission spectroscopy (ICP-OES) was used to study the damage of the substrate. Paramagnetic electron spin resonance spectroscopy (ESR) was used to investigate the defect structure of the coatings before and after a corrosion test. The results showed that the Si and O contents changed from 0at.%–7.6at.% and 2.21at.%–4.88at.% for samples S1 (Si~0at.%), S2 (Si~1.2at.%), S3 (Si~4.08at.%), and S4 (Si~7.6at.%), respectively. The Si and O atoms did not change the amorphous characteristics of the carbon matrix. With the increase of Si / O content, the organic component of the coating, namely, Si-(CH3)3, increased. Moreover, the sp2 cluster size in the Si / O-DLC coatings decreased, whereas the sp3 content increased. Electrochemical impedance spectroscopy (EIS) testing of the short-term corrosion performance showed that the coating effectively improved the corrosion protection of the coating by two orders of magnitude. Combined with the fitting results of the equivalent circuit, the S4 coating had the largest pore resistance (Rpore=369.07 kΩ·cm2 ) and charge transfer resistance (Rct=100 EΩ·cm2 ). Thus, the S4 sample exhibited superior corrosion resistance. The results of the potentiodynamic polarization tests showed that the presence of the coating effectively improved the pitting resistance of the substrate and that the corrosion resistance of the coating improved with the increase of the Si / O content. The S4 coating had the lowest corrosion current density of 109 pA·cm?2 , which was a fourfold decrease in the current density, compared with the S1 (DLC) coating. These findings validate the results of the EIS. According to the results of the potentiodynamic polarization test, the porosity Pp of the coatings gradually decreased with the increasing Si / O content. In addition, the S4 coating had the lowest porosity Pp of 0.13%, which was an order of magnitude lower than the porosity of the S1 (DLC) coating (1.83%). Combined with the XPS and FT-IR results, the high Si / O content increased the organic fractions in the coatings and decreased their porosity. The in-situ EIS results from the long-term (360 h) corrosion tests showed no significant changes in the EIS data for the coatings throughout the immersion cycle, indicating that they had excellent corrosion resistance throughout the immersion cycle. According to the results of the equivalent circuit fitting, the pore resistance (~350 kΩ·cm2 ) and charge transfer resistance (~100 EΩ·cm2 ) of the S4 coating were in the highest range throughout the immersion cycle with small variations, which indicated that the S4 coating had superior corrosion protection performance, compared with those of other coatings. Based on the surface morphology and Raman spectra of coated samples before and after corrosion, there were no significant changes, indicating that the coatings had excellent shielding properties. However, the ICP-OES results revealed that trace amounts of iron ions were dissolved in all the coated samples, indicating that slight metal corrosion still existed at the coating / substrate interface. Further, the ESR results confirmed that the defect densities of the coatings after prolonged immersion were higher than those before immersion. The excellent corrosion resistance of the coating with a high Si / O content was attributed to the increased organic components, which can reduce its porosity and prevent the penetration of corrosive ions. However, the coatings prepared via vapor phase deposition always have some defects, such as pores, and the corrosive solutions can enter the coating / metal substrate interface through those defective structures,which causes corrosion of the metal substrate. This method of co-doping of Si / O in the DLC coatings provides a novel solution by which to enhance the corrosion resistance of marine equipment, especially for long-term corrosion protection. |
| Key words: Si / O-DLC coating corrosion resistance long-term corrosion compactness |
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