类金刚石涂层在不同载荷和湿度下的摩擦特性

Friction Behavior of Diamond-like Coating Sliding against Steel at Various Loads and Relative Humidity

利用磁过滤阴极弧等离子体沉积装置在单晶硅基底上制备了类金刚石涂层 ,采用原子力显微镜和纳米压痕仪测定了其表面形貌及硬度 ,在 DF- PM型动 -静摩擦系数精密测定仪上考察了涂层在不同载荷及湿度下同 GCr15钢对摩时的摩擦性能 .结果表明 ,在不同环境湿度条件下 DL C涂层的摩擦性能明显不同 ,这主要归因于转移膜形成机理的不同 ;在 3N载荷下 ,DL C涂层同 GCr15钢对摩时的摩擦系数相对较小 ,且较为稳定 ;当环境湿度增大至 10 0 %时 ,摩擦系数显著增大 。

Diamond-like coatings (DLC) were deposited on the silicon substrate using a filtered cathodic arc plasma deposition system. The morphology and the hardness of the resulting DLC coatings were observed and determined with an atomic force microscope and a nano-indenter, respectively. The friction behaviors of the DLC coating sliding against SAE-52100 steel at various loads and relative humidities were investigated on a DFPM unidirectional friction coefficient measurement apparatus. The morphologies of the wear scars of the coating and the counterpart steel ball were observed with a scanning electron microscope. The results showed that the DLC coating sliding against the steel at a lower relative humidity registered a lower friction coefficient with small fluctuation, while the friction coefficient rose significantly at increased load and relative humidity. This was attributed to the different formation mechanisms of the graphitized transfer film on the counterpart steel surface. Since the graphitized transfer film formation of the DLC coating on the counterpart steel was restrained in the presence of water, the catastrophic destruction of the film occurred only after 400 slidings at a relative humidity of 100%. Thus the DLC coating prepared was not suitable for the protection of Si-based elements working in the environment of high relative humidity.