表面形貌和润湿性对钛合金摩擦学性能的影响

The impacts of the surface pattern and wettability on the tribological performance of Ti alloy

摘要:

为提高钛合金的摩擦学性能，采用激光加工技术在Ti6Al4V合金表面分别构建间距为100μm和300μm的网格和点阵结构，将SiO2纳米粒子涂覆在微结构上制备微纳结构。用接触角测量仪测量试样的表面接触角和滚动角；采用LEXT OLS4000 3D激光共焦显微镜进行表面形貌和磨痕表征，采用多功能摩擦磨损实验机(UMT)进行摩擦学性能测试。结果表明，具有微结构的表面是符合Wenzel状态的疏水表面，涂覆SiO2得到符合Cassie状态的超疏水表面。随着间距的增大润湿性增强，点阵表面比网格表面更易润湿。在50 mN载荷条件下，随表面疏水性的提高，表面减摩耐磨性增强。在5 N载荷条件下，涂覆SiO2显著增强表面的减摩耐磨性，且网格表面比点阵表面的耐磨性更强。

Abstract:

In order to improve the resistance of titanium alloy on the tribological characteristics, laser processing was used to build grid and dot micro-structure with spacing of 100μm and 300μm on Ti6Al4V alloy surface. The Nano-SiO2 powders were coated on the micro-structures to build micro-nano structures. The contact angles and roll angles were measured by contact angle measurement. The micrograph and wear tracks were investigated by LEXT OLS4000 3D microscope. Tribological performance were evaluated by CETR Universal Micro-Tribometer(UMT). The results show that the micro structure surface is in hydrophobic state that is in accordance with Wenzel model, while the surfaces with the micro-nano structure formed by coating the Nano-SiO2 is in super hydrophobic state that is in accordance with Cassie model. With the increase of spacing, the surface is more easily to be wet. The dot surface is more easily to be wet than grid surface. When the load is 50 mN, friction-reducing and wear protection of the surface enhance with weaken of surface wettability. When the load is 5 N, coating SiO2 can enhance wear resistance and friction-reducing of the surface significantly, while wear resistance of the gird surface is stronger than that of the dot.