温度对WC-WB-CoCr涂层高温摩擦磨损性能的影响

Effect of Temperature on High-Temperature Friction and Wear Properties of WC-WB-CoCr Coating

采用超音速火焰喷涂(HVOF)制备了WC-WB-CoCr涂层,研究了温度对WC-WB-CoCr涂层高温摩擦磨损性能的影响。通过SEM、XRD和显微硬度仪对涂层的微观组织、相结构和力学性能进行表征。通过摩擦磨损试验机和拉曼光谱仪研究了WC-WB-CoCr涂层的高温摩擦学性能和氧化产物,采用台阶仪扫描磨痕形貌并计算WC-WB-CoCr涂层的磨损率。结果表明:WC-WB-Co-Cr涂层主要由WC和CoW_(2)B_(2)组成,涂层结构致密,与基体结合紧密;随着磨损试验温度升高,涂层的摩擦系数从0.66降低到0.57,涂层的磨损率随着温度的升高而升高,但是其磨损率增长程度随着温度的升高而降低。在高温磨损过程中,磨痕表面的氧化膜主要由WO3和CoWO4组成,且CoWO4比WO3表现出更好的耐高温磨损性能。涂层的主要磨损机制为氧化磨损、疲劳磨损和粘着磨损。

WC-WB-CoCr coatings were prepared by high velocity oxy-fuel spraying(HVOF),and the effect of temperature on the frictional wear properties of WC-WB-CoCr coatings was investigated.The microstructure and mechanical properties of the coatings were characterized by SEM,XRD and microhardness tester.The high-temperature tribological properties and oxidation products of WC-WB-CoCr coatings were investigated by friction and wear testing machine and Raman spectroscopy,and the abrasion scar morphology was scanned and the wear rate of WC-WB-CoCr coatings was calculated by a surface profiler.The results show that the WC-WB-Co-Cr coating mainly consists of WC and CoW_(2)B_(2),and the coating structure is dense and tightly bonded to the substrate.The friction coefficient of the coating decreases from 0.66 to 0.57 as the temperature of the wear test increases,and the wear rate of the coating increases with the increase of temperature,but the growth rate of its wear rate decreases with the increase of temperature.During high temperature wear,the oxide film on the surface of the wear marks mainly consists of WO3 and CoWO4,and CoWO4 shows better high temperature wear resistance than WO3.The main wear mechanisms of the coating are oxidation wear,fatigue wear and adhesive wear.