脉冲激光沉积WSx/a-C复合薄膜的结构与摩擦学性能

采用脉冲激光烧蚀石墨/WS₂组合靶,在硅基片上沉积不同碳质量分数的WSx/a-C复合膜。用能谱仪、扫描电子显微镜和X射线衍射仪对薄膜的成分、形貌和微观组织进行了表征。采用纳米压痕仪、涂层附着力划痕仪和球-盘式摩擦磨损试验机对薄膜的硬度、结合力和大气中(相对湿度50~55%)的摩擦学性能进行了测试。结果表明,薄膜的S/W比稳定在2.0左右且形成了(002)择优取向的WS₂相。随着薄膜中碳质量分数的增加,薄膜的硬度在36.1%C时出现最高值,结合力随之增大且在52.4%C时达到最高值,摩擦因数先降低后增加,在41.2%C时有最小值0.144。薄膜磨损率在(0.91~1.61)×10_-15 m₃N_-1m_-1范围内变化,36.1%C的WSx/a-C复合膜具有最佳耐磨性能。

Microstructure and tribological properties of pulsed laser deposited WSx/a-C composite films

WSx/a-C composite films with various carbon contents were prepared on monocrystalline silicon substrate by ablating a set of graphite/WS₂ combined targets with pulsed excimer laser. The composition, morphology, microstructure and chemical state of the films were characterized by energy disperse spectroscopy (EDS), scanning electron microscopy (SEM), X-ray diffractometry (XRD) and X-ray photoelectron spectroscopy (XPS). The hardness, adhesion to substrate and tribological properties in air (RH=50~55%) of the films were evaluated by nano-indentation, scratch tester and ball-on-disk tribometer. The results show that the S/W ratio maintains a constant value about 2.0 and a WS₂ phase with (002) preferred orientation is formed in the films. With increasing carbon content, the hardness peaks at 36.1%C, the adhesion increases and a maximum value is reached at 52.4%C, the friction coefficient decreases first and then increases and a minimum value 0.144 is reached at 41.2%C. The wear rate varies in the range of (0.91~1.61) ×10_-15 m₃N_-1m_-1 and the film with 36.1%C shows the best wear resistance.