碳含量对中频磁控溅射沉积MoCN涂层微观结构及摩擦学性能的影响

目的 为了大幅提高机械零部件表面的硬度和耐磨性能，探究制备具有低摩擦因数、高硬度和良好耐磨性的MoCN涂层。方法 采用中频磁控溅射技术在不锈钢基板和硅片上，通过控制C₂H₂气体(纯度99.99%,0、3、6、9 mL/min)的量来制备具有不同含碳量的MoCN纳米复合涂层。通过X射线衍射仪和拉曼光谱仪分析涂层主要的物相结构，采用扫描电子显微镜(SEM)和原子力显微镜(AFM)表征涂层的表面和断面形貌。采用连续刚度法，利用纳米压痕仪测试涂层的纳米硬度和弹性模量。利用自动划痕试验机和光学显微镜(OM)评估涂层与基体之间的黏附强度。最后利用多功能摩擦磨损试验机进行磨损试验，通过SEM对试验后的涂层进行磨损形貌分析，并对涂层的摩擦学性能进行评价。结果 涂层微观组织和力学性能表征结果表明，MoCN涂层由MoN相和非晶态碳相组成。随着涂层中碳含量的增加，涂层与基体之间的结合力和涂层表面的粗糙度都呈现逐渐减小的趋势，其涂层的划痕失效临界载荷和表面粗糙度的最小值分别为6.90 N和6.80 nm，但是涂层的纳米硬度从7.36 GPa增至10.23 GPa。摩...

Effect of Carbon Content on the Microstructure and Tribological Properties of MoCN Nanocomposite Coating Prepared by Medium Frequency Magnetron Sputtering

In practical engineering application, in order to reduce the damage of parts in the process of friction and wear, coatings are often deposited on the metal surface to improve the wear resistance of parts. MoN coating is a candidate material for tool coating because of its excellent wear resistance. Moreover, by introducing C atom into MoN coating, C and N combine to form nanocomposite structure, which can effectively improve the hardness and anti-oxidation performance of MoN coating. The work aims to explore and prepare MoCN nanocomposite coating with low friction factor and good wear resistance to greatly improve the hardness and wear resistance of mechanical part surface. In this study, MoCN nanocomposite coatings with different carbon contents were prepared by controlling the amount of C2H2 gas (99.99% purity, 0 mL/min, 3 mL/min, 6 mL/min and 9 mL/min) on stainless steel substrates and silicon wafers with medium frequency magnetron sputtering. The effects of carbon content on the microstructure, mechanical properties and tribological properties of the coatings were investigated. The main phase structure of the coating was analyzed by X-ray diffraction and Raman spectroscopy. Scanning electron microscopy (SEM) and atomic force microscopy (AFM) were used to characterize the surface and section morphology of the coating. The nano-hardness and elastic modulus of the coating were measured by continuous stiffness method and Nano-indentation. The adhesion strength between the coating and the substrate was evaluated by automatic scratch tester and optical microscope (OM). Finally, the wear test was carried out by the multifunctional friction and wear tester, the wear morphology of the tested coating was analyzed by SEM, and the tribological properties of the coating were evaluated. According to the characterization results of coating microstructure and mechanical properties, MoCN coating was a polycrystalline structure composed of MoN phase and amorphous carbon phase. With the increase of carbon content, the surface roughness of the coating decreased from 11.60 nm to 6.80 nm, and the coating grains were refined. From the cross-sectional morphology of the coating, it could be observed that the MoN coating grew in an obvious loose columnar shape and there were a large number of microporous defects. With the doping of carbon, the columnar crystal growth mode was gradually refined to form a dense microstructure. In addition, from the mechanical property characterization results, it could be seen that the carbon content of the coating had a significant impact on the mechanical properties of the coating. The main performance was that with the increase of carbon content in the coating, the hardness of the coating increased from 7.36 GPa to 10.23 GPa, showing a gradual increasing trend. At the same time, the ability to resist elastic-plastic deformation was gradually enhanced. However, during the scratch test, the abrupt load of acoustic emission signal decreased from 13.80 N to 6.90 N, indicating that the adhesion strength of the coating decreased gradually due to the increase of residual stress. During the wear test, the amorphous carbon element in the coating had a good lubrication effect after graphitization. Therefore, with the increase of carbon content in the coating, the friction coefficient of the coating decreased from 0.85 to 0.51. The wear resistance of the coating was enhanced. The main wear mechanisms in the wear process were adhesive wear, abrasive wear and spalling. It can be seen that with the increase of carbon content in the coating, the columnar growth mode of the coating is gradually refined to form a dense microstructure, and the mechanical and tribological properties are gradually improved.