铌对Ni60激光熔覆层显微组织及耐磨性能的影响

Effects of Nb on Microstructure and Abrasive Wear Resistance of Laser Clad Ni60 Alloy Coating

采用激光熔覆送粉法制备了Ni60合金及铌修正的Ni60合金激光熔覆层。采用扫描电子显微镜、能谱、电子背散射衍射技术及磨损试验研究了铌对复合熔覆层显微组织、相成分及耐磨性能的影响。结果表明,加入铌后提供了富铌的形核剂,减少了CrB沉淀相的结构尺寸。熔覆层中Cr7C3的生长被抑制,降低了熔覆层中粗大碳化物相的比例。与纯的Ni60合金熔覆层相比,铌修正的复合熔覆层显微硬度下降了33%,但是铌修正的复合熔覆层的耐磨性能却提高了5倍。

Laser deposited coatings were made from Ni60 alloy and Nb-modified Ni60 alloy using la- ser cladding with powder injection. The effect of Nb on microstructure, phase composition and wear property of the composite coating were investigated by means of scanning electron microscopy （SEM）, energy dispersive spectroscopy （EDS）, electron backscatter diffraction （EBSD） and wear test. Addition of Nb was done to decrease the structural scale of CrB precipitates by providing Nb-rich nucleation a- gents. The growth of Cr7C3 was suppressed in the coating, resulting in a decrease in aspect ration of coarse carbide. Compared with the pure Ni60 alloy coating, the microhardness of the Nb-modified com- posite coating was decreased about 33%, but the wear resistance of the Nb-modified composite coating was increased five times.