Yan Zhen, Sui Xudong, Yan Mingming, Liu Jian, Zhang Shuaituo, Hao Junying, Li Wensheng, Liu Weimin
State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Science, Lanzhou 730000, China.
Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing 100049, China.
ACS Appl Mater Interfaces. 2020 Dec 16;12(50):56632-56641. doi: 10.1021/acsami.0c18996. Epub 2020 Dec 3.
Atomic oxygen (AO) has an important influence on the performance of solid lubricating materials applied in space. The tribological behaviors of both sputtered WS films without and with a dense layer were mainly investigated under the ex situ AO irradiation condition. AO irradiation results in the worse tribological property for the WS film without a dense layer. On the contrary, it is surprising that the WS film with the dense layer exhibits a lower friction coefficient after irradiation, which is different from the reported results that the solid lubricating films always increased the friction and wear because the surfaces of the films were oxidized by AO. Meanwhile, it is found that the generated W oxides contributes to the partial surface of the wear track becoming smooth because of the shear and slip of crystal planes for WS crystals on the surface of the dense layer. Eventually, the lubricating mechanisms of the irradiated WS films are also revealed via correlating the friction and wear characteristics of the films.
原子氧（AO）对应用于太空的固体润滑材料的性能有重要影响。主要研究了在非原位AO辐照条件下，有无致密层的溅射WS薄膜的摩擦学行为。AO辐照导致无致密层的WS薄膜的摩擦学性能变差。相反，令人惊讶的是，有致密层的WS薄膜在辐照后表现出较低的摩擦系数，这与报道的固体润滑薄膜因表面被AO氧化而总是增加摩擦和磨损的结果不同。同时，发现生成的W氧化物有助于磨损轨迹的部分表面变得光滑，这是由于致密层表面WS晶体的晶面发生剪切和滑移。最终，通过关联薄膜的摩擦和磨损特性，揭示了辐照后WS薄膜的润滑机制。
