采用等离子体增强气相沉积制备了类金刚石薄膜,利用原子力显微镜的轻敲模式观察了它们的形貌,并在考虑外加载荷和扫描速度的基础上,用摩擦力显微镜(FFM)对比考察了尖端探针和平头探针对类金刚石薄膜摩擦性能评价的影响。结果表明:类金刚石薄膜的表面粗糙度随基底负偏压的增加而减小;存在于探针和类金刚石薄膜之间的水膜对尖端探针的剪切阻力贡献较大,且尖端探针测得的摩擦力变化趋势受扫描速度影响显著;水膜对平头探针起着不同形式的润滑作用,从而导致平头探针和类金刚石薄膜之间摩擦性能的速度效应存在差异;利用摩擦力显微镜考察类金刚石薄膜的摩擦性能时,存在着明显的针尖尺寸效应。
Diamond-like Carbon (DLC) thin films were prepared by Chemical Vapor Deposition (CVD) method. Their morphology was observed with the AFM Tapping mode, and the adhesive forces were also measured respectively. The effects on the tribological properties of DLC thin films investigated with a sharp tip and a plateau tip were compared when the applied load and scanning velocity were taken into account. It is found that the surface roughness goes smaller with the increment of substrate bias voltage, but the trend of adhesion is reverse; The contribution of shear resistance, which is caused by the water film that occurs between the sharp tip and DLC thin films, to the measured friction is significant. Purther, there exists critical scanning velocity in the change of friction obtained with the sharp tip. However, the water film plays manifold lubricative roles during the sliding process for the plateau tip, which leads to the velocity effect's discrepancy of the tribological properties between the DLC thin film and plateau tip pairs. Tip size effect is evident in the study of DLC thin films' frictional behavior with the FFM.