激光熔覆WC/Ni60B复合涂层在水润滑滑动摩擦环境下的磨损特性

采用激光熔覆技术制备了Ni60B镍基合金涂层以及微米WC、纳米WC和微-纳米WC颗粒增强的Ni60B基复合涂层（分别称为WCm、WCn和WCmn复合涂层）.对制备涂层在Amsler200磨损试验机上进行了不同载荷和滑动距离的水润滑滑动磨损试验.结果表明:WC颗粒的加入显著提高了Ni60B涂层的耐磨性.WCm复合涂层和纳米WCn复合涂层的耐磨性差别不大，但磨损形貌不同.涂层在水润滑环境下的磨损量均远远低于干滑动摩擦，其原因是水膜的支撑或隔离作用降低了涂层与磨轮之间的接触应力，水的冷却作用减少了摩擦热引起的温度升高，降低了涂层摩擦表面的温升和热软化.水润滑摩损条件下，WCm和WCn复合涂层中过饱和W元素发生扩散和聚集. 

Wear behavior of laser cladding WC/Ni60B composite coatings under water lubrication sliding condition

Ni60B nickel based alloy coatings and micro WC, nano WC and micro-nano WC particle reinforced Ni60B composite coatings were fabricated using laser cladding technology, hereinafter called as WCm, WCn and WCmn coatings,respectively. Sliding wear tests at different loads and sliding distances were conducted for the coatings using an Amsler200 tester under water lubrication conditions. The results show that the addition of WC particles can improve the wear resistance of Ni60B coatings and that the wear resistance of the WCm and WCn coatings does not presentan obvious difference, however their worn morphologiesare different. The wear resistance of the coatings is much better under water lubrication than dry sliding wear because the water lubrication film can play a support or isolating action between the coatings and the wear wheel, which decreases their contact stress, and because water cooling to friction couples decreases the temperature rising and the softening of the coatings. W element which is saturated in the WCn and WCm-coatings diffuses and agglomeratesduring water lubrication wear.