MoS2/Ti-WC纳米多层薄膜结构设计及其宽温域摩擦性能研究

^{目的 探究环境温度对MoS2/Ti-WC纳米多层薄膜摩擦磨损性能的影响，探讨并揭示薄膜在高温环境下的损伤机理。方法 采用非平衡磁控溅射技术制备MoS2/Ti-WC纳米多层薄膜，评价Ti、WC双功能组元以及纳米多层结构设计对薄膜表面形貌和微观结构的影响。利用X射线衍射仪(XRD)、扫描电镜(SEM)、扫描探针显微镜(SPM)等表征手段对薄膜的晶体结构、表截面形貌以及表面粗糙度进行分析，利用原位纳米压痕仪对薄膜的力学性能进行评估，利用高温摩擦磨损试验机评价薄膜在不同温度环境(25~300 ℃)下的摩擦磨损性能，进一步通过激光共聚焦对磨痕和磨斑进行光学形貌分析，并利用能谱仪(EDS)和共聚焦显微拉曼光谱(Micro-Raman)对钢配副表面的摩擦转移膜进行成分分析。最终揭示MoS2/Ti-WC纳米多层薄膜在不同温度下的磨损机理。结果 MoS2/Ti-WC纳米多层的结构设计可以诱导MoS2 (002)晶面的择优生长，获得表面平整光滑、结构致密的薄膜。相比于MoS2/Ti薄膜，WC纳米层的引入，赋予薄膜更高的硬度和硬/弹比。MoS2/Ti-WC纳米多层薄膜在潮湿空气中的平均摩擦因数为0.07，平均磨损率为}6.14×10^–7 mm³/(N.m)^{。结论 MoS2/Ti-WC纳米多层薄膜在宽温域(100~300 ℃)内保持稳定的摩擦性能，这得益于薄膜纳米多层的结构设计、高的硬/弹比以及优异的抗氧化性能，同时在钢配副表面形成了连续且致密的转移膜。}

Structure Design and Tribological Properties of MoS2/Ti-WC Nano-multilayer Films with Environmental Adaptability in Wide Temperature Range

The rapid advancement of machinery industry has spurred a heightened demand for mechanical equipment components that can withstand extreme conditions, including high speed, heavy load, and elevated temperature. Solid lubricating films, such as MoS2, have emerged as pivotal technologies in enhancing the longevity of such components. However, traditional MoS2 coatings are susceptible to oxidation when exposed to atmospheric or humid conditions. Consequently, there is an urgent imperative to develop a new type of MoS2-based functional protective film that offers resilience against harsh environment while simultaneously exhibiting low friction and wear characteristics, thereby ensuring prolonged safety and reliability of critical mechanical elements during operation. In response to this critical need, the work aims to fabricate MoS2/Ti-WC nano-multilayer films by non-equilibrium magnetron sputtering technology and examine the impact of Ti and WC bifunctional components, as well as the structure of nano-multilayer film structure on the crystal structure of MoS2. Various characterization techniques, including X-ray diffraction (XRD), scanning electron microscopy (SEM), scanning probe microscopy (SPM), were employed to meticulously analyze the crystal structure, surface cross section morphology, and surface roughness of the films. Furthermore, the mechanical properties of the films were evaluated with an in-situ nano-indentation instrument, while their friction and wear performance at different temperature (ranging from 25 ℃ to 300 ℃) were assessed by a high-temperature friction and wear test machine. The optical morphology of the wear scar and wear debris was analyzed with laser confocal microscopy. The composition of the friction transfer film on the steel surface was investigated with energy dispersive spectrometer (EDS) and confocal micro-Raman spectroscopy (Micro-Raman). The wear mechanism at high temperature was also discussed. The structure design of MoS2/Ti-WC nano-multilayers could induce preferential growth of the MoS2 (002) crystal plane, resulting in a film with a smooth surface and dense structure. Compared to the MoS2/Ti film, the inclusion of WC nanolayers conferred higher hardness (~9.99 GPa) and a hardness-to-elasticity ratio of 0.090 to the film. MoS2/Ti-WC nano-multilayer films exhibited an average friction coefficient of 0.07 and an average wear rate of 6.14×10–7 mm3/(N.m) in humid air conditions. At temperature ranging from 100 to 200 ℃, the multilayer films demonstrated lower friction coefficients and excellent high-temperature stability. Especially at 100 ℃, the average friction coefficient of the multilayer films was below 0.02, with an average wear rate as low as 0.44×10–7 mm3/(N.m). When the ambient temperature rose to 300 ℃, the MoS2/Ti-WC nanolayered film still maintained a low friction coefficient (~0.08) and an average wear rate (2.33×10–7 mm3/(N.m)) under high-temperature conditions. This was attributed to the structure design of the nanolayered film, high hardness- to-elasticity ratio, excellent antioxidation performance, and structural stability. Additionally, the film components at the sliding interface underwent oxidation phase transformation into MeOx nanoparticles under high temperature and high contact stress. These nanoparticles interacted with MoS2 (002) nanosheets and formed a continuous and dense transfer film on the steel counterpart surface. These research findings have significant implications for the development of novel high-temperature lubricating materials in terms of structure and composition design.