掺W类金刚石薄膜的高温摩擦学行为

采用阳极层流型离子源结合非平衡磁控溅射技术制备了含氢掺钨类金刚石(W-DLC)薄膜,利用TEM、SEM、XRD、Raman光谱仪和摩擦磨损试验机等方法分析了薄膜的结构、形貌以及在高温下的摩擦学性能,探讨了W-DLC薄膜在高温下摩擦磨损行为作用机理.结果表明:W-DLC薄膜中钨原子以WC1-x纳米晶团簇的形式随机分布于碳基质中,增强了薄膜的韧性.W-DLC薄膜在25~200℃范围内的摩擦系数可稳定在0.1以下,在300℃时的摩擦系数则高达0.5,当试验温度进一步升高到400℃时,薄膜的摩擦系数反而降低至0.3左右,当试验温度升高到500℃时,W-DLC薄膜中的W被氧化生成WO_3和摩擦诱导生成的石墨共同作用,使得薄膜的摩擦系数降到0.15左右,说明W-DLC薄膜在高温下仍然具有优异的减摩特性.然而,W-DLC薄膜的磨损率在25~500℃范围内表现出随着温度的升高而不断增大的趋势.

High Temperature Tribological Behavior of W-Doped Diamond-like Carbon Films

In this study,W-doped diamond-like carbon films(W-DLC)were deposited by anode layer ion source combined with unbalanced magnetron sputtering.The structure,micro morphology and high temperature tribological properties were investigated by transmission electron microscopy,scanning electron microscopy,X-ray diffraction,Raman spectroscopy and an UMT-3 tribometer.The results show that nanometer sized tungsten carbide crystals were dispersedly embedded in the amorphous carbon matrix.The high temperature tribological behaviors of W-DLC films were systematically studied ranging from 25 ℃ to 500 ℃.The incorporation of W atoms into the DLC film improved the high temperature tribological stability and toughness as well.The structure and tribological properties were stable up to 200 ℃.The graphitization and oxidation of carbon were observed at 300 ℃,which deteriorated the wear resistance of as-deposited DLC films.The formation of WO3 was detected on the worn surface above 400 ℃.The coefficient of friction was as low as 0.15 at 500 ℃ while the wear rate was much higher than that under 200 ℃.