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

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 CoW2B2, 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.