NiCrBSi超音速火焰喷涂层在不同温度下的磨损行为

Wear behavior of NiCrBSi coatings produced by HVOF

采用超音速火焰喷涂在铸铁表面制备了NiCrBSi喷涂涂层,以研究其在不同温度下的摩擦磨损行为.采用pin-on-disc试验设备在室温和300℃下对NiCrBSi涂层进行了摩擦磨损试验,分析了温度对NiCrBSi涂层摩擦系数和磨损率的影响规律;采用XRD和SEM对NiCrBSi喷涂态涂层进行了微观组织结构分析;通过SEM对涂层磨损样品的表面和截面进行了微观组织观察,探索涂层在不同温度下的磨损机制.结果表明,NiCrBSi涂层结构致密,具有典型的喷涂层状结构,主要由γ-Ni相、Cr_(7)C_(3)相、Ni_(3)B相和CrB相组成;孔隙率为1.11%,硬度为742 HV0.1±24 HV0.1.NiCrBSi涂层在室温下发生明显的粘滑现象,随着试验温度的升高,涂层的摩擦系数降低;升高的试验温度导致涂层硬度降低,涂层磨损率升高,耐磨性能下降.涂层在室温及300℃下的磨损机制由磨粒磨损和疲劳磨损组成,随着温度的升高,磨粒磨损越加严重.

A NiCrBSi coating was produced on the surface of cast iron by high-velocity-oxygen-fuel spraying to investigate the wear behavior at different temperatures.The wear behavior was evaluated by pin-on-disc tester at room temperature and 300℃.The effect of temperature on friction coefficient and wear rate was analyzed.The phase and microstructure of the coating were analyzed by XRD and SEM.The worn surface and cross section of NiCrBSi coating were observed by SEM.The results showed that NiCrBSi coating was dense and exhibited typical lamellar structure.The coating was composed ofγ-Ni,Cr_(7)C_(3),Ni_(3)B and CrB.The porosity was 1.11%and the hardness was 742 HV0.1±24 HV0.1.At room temperature,stick-slip phenomenon was observed.With the increase of temperature,the friction coefficient of NiCrBSi coating decreases,but the wear rate increases and the wear resistance decreases.The wear was mainly caused by abrasive wear and fatigue wear at both temperatures.With the increase of temperature,abrasive wear becomes more and more serious.