射频非平衡磁控溅射WS_2薄膜的结构及其摩擦学性能研究

采用射频非平衡磁控溅射技术制备了具有不同(002)择优取向程度的WS2薄膜,研究了Ar流量对薄膜成分、微观结构、力学性能和摩擦学性能的影响.研究表明:随Ar流量的增大,WS2薄膜的S/W原子比和(002)衍射峰强度均表现出先降低后升高的变化趋势,而硬度和弹性模量表现出先升高后降低的变化趋势.在大气环境下,WS2薄膜的(002)择优取向程度、S/W原子比以及硬度对薄膜的摩擦学性能均具有显著影响,当S/W原子比较低、(002)择优取向度弱、硬度较高时,薄膜脆性较大,易于发生润滑失效;当S/W原子比、(002)择优取向度和硬度均较高时,薄膜结构致密,且摩擦过程中在对偶表面易于形成有效的转移膜,薄膜表现出较好的减摩、抗黏着特性和优异的抗磨性能.

Structural and Tribological Properties of WS2 Films Deposited by Radio Frequency Unbalanced Magnetron Sputtering

WS₂ films with different degree of(002) preferential orientation were deposited on n-(100) Si substrates by radio frequency unbalanced magnetron sputtering. The chemical composition and microstructure of WS₂ films were characterized by energy dispersive X-ray spectroscopy and X-ray diffractometer, scanning electron microscopy. The mechanical and tribological perperties were measured by nano-indentation and tribo-meter in ball-on-disk mode. The results show that the tribological performance of WS₂ films in terrestrial was influenced by Ar flow rate. With the increment of Ar flow rate, the S/W ratio of the films firstly decreased, and then increased. The trend of (002) diffraction peak was in consistent with the S/W ratio, while hardness and elastic modulus were opposite to the S/W ratio. It is found that the failure took place quickly for WS₂ films with the low S/W ratio, high hardness and poor crystallinity of WS₂ films. Inversely, when the relatively high S/W ratio and sharp (002) diffraction peak simultaneously appeared, the low friction coefficient and excellent wear resistance were obtained as the effective transfer films presented. However, the wear resistance declined since the hardness of WS₂ films was not high enough to bear load.