热处理对钽强化激光熔覆NiCrBSi涂层的影响

通过在激光熔覆NiCrBSi涂层(Ni60)中添加钽(Ta)元素来提高900℃热处理后涂层的耐磨性.研究了900℃热处理对激光熔覆NiCrBSi和钽强化NiCrBSi复合涂层显微组织、硬度以及耐磨性能的影响.利用带能谱仪的扫描电镜和衍射仪分析涂层的显微组织和物相.通过盘-销实验评价涂层的耐磨性.结果表明:经过900℃热处理后涂层中的M7C3和M23C6发生了分解,钽强化复合涂层和纯NiCrBSi涂层中的硬度都有所下降,但由于复合涂层中原位生成的TaC未发生分解,使得其硬度和耐磨性都高于纯NiCrBSi涂层.

Influence of Heat Treatment on Laser Clad Ta Reinforced NiCrBSi Coating

Tantalum element was used to improve wear resistance of laser clad NiCrBSi coating (Ni60) heat treated at 900 °C. Microstructure, microhardness and wear resistance of the pure NiCrBSi and Ta reinforced NiCrBSi coatings were investigated. The coatings were analyzed by scanning electron microscope (SEM) with energy energy-dispersive spectrometer (EDS). The phase constitution was identified using X-ray diffraction (XRD) experiments. Dry sliding wear tests were carried out on a pin-on-disc tribometer to study wear behavior. The results show M7C3 and M23C6 carbides were decomposed after 900 °C heat treatment, which resulted in the decrease in the microhardness of the coatings. However, after the heat treatment, the Ta reinforced NiCrBSi composite coating had higher microhardness and wear resistance compared to pure NiCrBSi coating since in situ TaC particles in the composite coating were not decomposed due to its high thermal stability.