溅射功率对La-Ti/WS2 复合薄膜高温摩擦学行为的影响

Effect of Sputtering Power on High Temperature Tribolo-gical Behavior of La-Ti/WS2 Composite Films

摘要:

高温条件下WS₂易于氧化生成WO₃，导致WS₂固体润滑薄膜的摩擦学性能受到较大影响。为改善WS₂固体润滑薄膜在高温条件下的摩擦学性能，采用非平衡磁控溅射技术制备了共掺杂La-Ti/WS₂复合薄膜，研究了靶功率对磁控溅射La-Ti/WS₂复合薄膜结构和高温摩擦学性能的影响。利用扫描电镜（SEM）、X射线衍射仪（XRD）、纳米压痕仪和X射线光电子能谱仪（XPS）分析了薄膜微观形貌、成分、力学性能、微观结构。利用高温摩擦磨损试验机研究了复合薄膜的高温摩擦学性能。结果表明，高温环境下，靶功率为20 W时La-Ti/WS₂复合薄膜表现出优异的摩擦学性能。此时，复合薄膜H/E值最大，摩擦系数最小，平均为0.012，磨损率最低为1.56×10^-8 mm³/N·m，这主要归因于高温下摩擦界面产生的稀土氧化物，促使La-Ti/WS₂复合薄膜的摩擦磨损机制发生了改变，使得WS₂在高温受破坏的情况下仍然具有优异的摩擦学性能，从而进一步拓展了WS₂复合薄膜的工程应用范围。

Abstract:

Under high temperature conditions, the crystal WS₂ is easily oxidized to WO₃, which has a great impact on the tribological properties of WS₂ solid lubrication films. In order to improve the tribological properties of WS₂ solid lubricating films at high temperatures, the co-doped La-Ti/WS₂ composite films were prepared by unbalanced magnetron sputtering. The effects of target power on the structure and tribological properties of La-Ti/WS₂ composite films were studied. The micromorphology, composition, mechanical properties and microstructure of the films were analyzed by scanning electron microscopy (SEM), X-ray diffraction (XRD), nano indentation and X-ray photoelectron spectroscopy (XPS). The high temperature tribological properties of composite films were researched by high temperature friction tester. The results show that La-Ti/WS₂ composite films show excellent tribological properties when the target power is 20 W at high temperature. At this time, the H/E value of the composite film is the largest, the friction coefficient is the smallest with the average value of 0.012, and the wear rate is the lowest, which is 1.56×10^-8 mm³/N·m. This is mainly due to the production of rare earth oxides at the friction interface at high temperatures, which change the friction and wear mechanism of La-Ti/WS₂ composite film, so that WS₂ still has excellent tribological properties when it is damaged at high temperature, further expanding the scope of engineering application of WS₂ composite films.