采用大气等离子喷涂技术制备了CoCrAl-B4C涂层,测试了涂层的硬度、结合强度、热震性能及不同条件下的摩擦系数。结果表明:涂层的平均显微硬度为980HV0.2,平均结合强度为17.5MPa,经900℃水淬热震循环10次仍然完好;涂层经700℃热处理后,摩擦系数较低且波动小,水蒸气的存在有利于涂层摩擦系数的降低,其主要原因是涂层表面在热处理与摩擦过程中生成了B2O3 和H3BO3 自润滑相。

CoCrAl-B4C coating was successfully deposited by air plasma spray technology. The coating micro-structure, microhardness, bonding strength, thermal shock and tribological performance were analyzed. The results show that the microhardness and bonding strength of CoCrAl-B4C coating are 980HV0.2 and 17.5 MPa respectively, and no failure occurs after ten time’s thermal shock tests at 900℃; The lower friction coefficients of CoCrAl-B4C coating appear when the coating in water vapor atmosphere or preheating treatment at 700 ℃, which are attributed to the formation of B2O3 and H3BO3 lubricating phases on the worn surface.