| 引用本文: | 廖毓,吕健,徐凯,娄明,常可可.Ti(C,N)基多碳化物金属陶瓷的物相结构与表面氧化行为[J].中国表面工程,2024,37(6):324~331 |
| LIAO Yu,LÜ Jian,XU Kai,LOU Ming,CHANG Keke.Phase Structures and Surface Oxidational Behaviors of Ti(C, N)-based Cermets Incorporating Multi-carbides[J].China Surface Engineering,2024,37(6):324~331 |
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| Ti(C,N)基多碳化物金属陶瓷的物相结构与表面氧化行为 |
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廖毓1，2，3，吕健1，徐凯2，娄明2，常可可2
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1.江西理工大学材料科学与工程学院 赣州 341000 ；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.国家稀土功能材料创新中心 赣州 341101
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| 摘要: |
| 深地钻探高温、氧化、冲蚀的苛刻服役环境对金属陶瓷复合材料的强韧、抗氧化等性能提出更高的要求。在常规商用多碳化物（WC、Mo2C）金属陶瓷体系的基础上，进一步添加 TiC、TaC 制备了两种 Ti(C,N)基金属陶瓷，并重点对其物相结构、力学性能和抗氧化性能进行研究。结果表明，两种多碳化物金属陶瓷的物相结构均包含(Ti,M)(C,N)(M=W、Mo、Ta)硬质相和(Co,Ni)粘结相；相较于 TiC 添加金属陶瓷，含 TaC 金属陶瓷的硬质相颗粒尺寸更大、强韧匹配更好。热力学计算结果表明，Ta 原子在粘结相中的固溶度低于 Ti 原子，因而更易通过“溶解-析出”过程促进硬质相长大，起到增韧效果。在高温氧化环境中，Ta5+可以替换 TiO2氧化层中的 Ti4+，使得该氧化层中的 O 空位浓度降低、O 原子扩散系数增大，因而提升了金属陶瓷的抗氧化性能。上述研究结果显示了 TaC 在增强 Ti(C,N)基金属陶瓷力学性能和抗氧化性能方面的重要作用，有望指导未来金属陶瓷新体系的研发。 |
| 关键词: 金属陶瓷 TiC TaC 物相结构 抗氧化性能 |
| DOI：10.11933/j.issn.1007-9289.20231230002 |
| 分类号:TG156；TB114 |
| 基金项目:中国科学院战略性先导科技专项（XDB0470103）；宁波市自然科学基金（2023J338）；宁波市 3315 创新团队（2019A-18-C） |
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| Phase Structures and Surface Oxidational Behaviors of Ti(C, N)-based Cermets Incorporating Multi-carbides |
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LIAO Yu1，2，3，Lü Jian1，XU Kai2，LOU Ming2，CHANG Keke2
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1.College of Materials Science and Engineering, Jiangxi University of Science and Technology,Ganzhou 341000 , China ；2.Key Laboratory of Advanced Marine Materials, Ningbo Institute of Materials Technology and Engineering,Chinese Academy of Sciences, Ningbo 315201 , China ；3.National Rare Earth Function Materials Innovation Center, Ganzhou 341101 , China
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| Abstract: |
| Cermet materials that combine the strength of ceramic phases and the toughness of metallic phases are among the critical material categories for surface strengthening of steel drilling tool components, such as stabilizers and bearings. In recent years, deep drilling activities toward continental and oceanic crust have boomed, during which harsher working conditions involving high temperature, oxidation, and erosion have been typically encountered. In this regard, the strength-toughness properties and oxidation resistance of cermet materials must be further optimized to guarantee the service life of drilling tool components in deep drilling applications. Based on commercial cermet systems that require the addition of multi-carbides (e.g., WC and Mo2C) to enhance sinterability, in this study, two types of Ti(C,N)-based cermet samples incorporating TiC and TaC, namely Ti(C,N)-10%TiC-15%WC-8%Mo2C-9%Co-9%Ni and Ti(C,N)-10%TaC-15%WC-8%Mo2C-9%Co-9%Ni were prepared, following the powder metallurgical procedures comprised of ball milling, uniaxial pressing, and vacuum sintering. The phase compositions, mechanical properties, and oxidation behaviors of the as-sintered samples were examined using experimental and computational methods. The X-ray diffraction measurements revealed that both cermets consisted of (Ti,M)(C,N) (M=W,Mo,Ta) ceramic phase and (Co,Ni) binder phase, where the ceramic phase exhibited typical core-rim structures that could form in the Ti(C,N)-based cermets containing multi-carbides through the “dissolution–precipitation” process. The electron microscopic analyses further showed that in comparison to the TiC added cermet sample with its ceramic particle size typically ranging between 0.8 and 1.2 μm, the sample incorporating TaC possessed coarser ceramic particles (mostly in a range of 1.2-1.6 μm). According to the indentation fracture measurements conducted at 98 N, the cermet sample with TaC addition exhibited better hardness–toughness match (1 463 HV10 and 11.7 MPa·m1 / 2), as compared with those of the TiC-added cermet sample (1 471 HV10 and 10.8 MPa·m1 / 2). Based on the CALPHAD (CALculation of PHAse Diagrams) method, the solid solubility of Ta in the binder phase was found to be lower than that of Ti, which could facilitate the growth of ceramic particles, thus contributing to the increased density and fracture toughness. The high-temperature oxidation tests were conducted at 800 ℃ for different durations (6 and 12 h), and the mass gains of the two cermet samples were measured. Lower mass gains were recorded for the TaC-added cermet sample, which corresponded to a ~37% enhancement in the oxidation resistance compared with the TiC-added cermet sample. The cross-sections of the oxidized samples were prepared and examined to rationalize the surface oxidational behavior of these two cermet samples. Both cermet samples exhibited oxidation stratification, where the outer oxide layers were enriched with Co, Ni, Mo, and W, and the inner oxide layers were rich in Ti and Ta. The thermodynamic calculations (i.e., the Ellingham diagrams) showed that both TiO2 and Ta2O5 possessed more negative Gibbs free energies of formation compared with other types of oxides (NiO, CoO, MoO3, and WO3), which suggested high propensities of TiO2 and Ta2O5 formation during the inception of high-temperature oxidation. In addition, the first-principles calculations performed in relevant research have suggested that upon exposure to high-temperature oxidation, Ta5+ might partially replace Ti4+ in the TiO2 layers, which could decrease the number of O vacancies and increase the diffusion coefficient of O in the oxide layers, thus benefiting the oxidation resistance of the cermet materials. Hence, the results demonstrated in the current study described the critical role of TaC addition in ameliorating the mechanical and oxidational properties of Ti(C,N)-based cermets containing multi-carbides. The underlying mechanisms were discussed using thermodynamic calculations, which could help guide the future development of cermet materials for deep-drilling applications. |
| Key words: cermets TiC TaC phase constitutions oxidation resistance |
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