超细晶TiNi表面磁控溅射CNx薄膜的纳米压痕与摩擦性能

Nanoindentation and Friction Properties of Magnetron Sputtered CNx Films on Ultrafine Grained TiNi Alloy

摘要:

采用室温磁控溅射技术在超细晶TiNi合金表面制备出CNx/SiC(氮化碳/碳化硅)双层薄膜，SiC为中间层。研究了CNx薄膜的组织结构、纳米压痕和摩擦性能。结果表明：CNx薄膜存在微孔缺陷 (基体中夹杂物脱落等原因引起)、石墨含量高、纳米硬度(5.23 GPa)低、弹性模量(33.29 GPa)低，但具有高的硬度与弹性模量比值 (0.157)。在200 g载荷、氮化硅球(半径为2 mm)为对摩件、大气干摩擦条件下，CNx薄膜的摩擦系数约为0.173，磨损后薄膜未出现裂纹和剥落；在500 g载荷、室温Kokubo人体模拟体液下，CNx薄膜的摩擦系数约为0.103，但磨损后薄膜出现剥落。剥落的发生可能是由于SBF溶液通过微孔缺陷进入并腐蚀薄膜-薄膜-基材界面所致

Abstract:

The microstructure, nano-indentation and friction properties of the CNx/SiC (carbon nitride/silicon carbon) bilayered films (SiC as interlayer), deposited on ultrafine-grained TiNi alloy substrate using magnetron sputtering technique at room temperature, were investigated. The results show that the CNx film is not fully compact with micro-pore defections in some zones, which has been possibly caused by the breaking off of inclusions in substrates. The CNx film presents high concentration graphite, low nano-hardness (5.23 GPa), low Young's modulus (33.29 Pa), but high hardness-to-modulus ratio (0.157). As sliding against Si3N4 (silicon nitride) balls (2 mm in radius), under ambient environment and 200 g load, the CNx film exhibits the friction coefficient of about 0.173 without film cracking and interface delaminating. On the other hand, under Kokubo simulation body fluid (SBF) and 500 g load, the CNx film exhibits the friction coefficient of about 0.103, but the interface delaminating occurs that is believed to be due to that the SBF enter into the film-film-substrate interfaces through micro-pores defections and corrode the interfaces