中文摘要：

在304不锈钢表面采用半导体激光熔覆制备Ni包B4C涂层,研究激光加工参数对涂层的组织形貌、物相组成、硬度和耐磨性能的影响。结果表明,当激光功率为3 k W和扫描速度为6 mm/s时,熔覆层无气孔、无裂纹,与基体呈冶金结合;熔覆层的显微组织为枝晶共熔体和再生的二次枝晶,熔覆层的主要物相由γ-Ni,Ni4B3,Fe3C,B4C,B13C2,Cr3Ni2,（Fe,Ni）23C6和Fe23（C,B）6等组成;熔覆层具有较高的硬度（平均值为900 HV0.2）,耐磨性是基体的7.6倍,硬度和耐磨性的提高归因于熔覆层中未完全熔解的B4C颗粒以及新形成的强化相和硬质相。

英文摘要：

Ni-coated B4C coatings were prepared on the surface of 304 stainless steel by semiconductor laser cladding. The effect of laser processing parameters on microstructure, phase composition, microhardness and wear resistance of the coatings was investigated. The results show that the cladding layer has a good metallurgical bonding to the substrate, and no defects such as pores and cracks appear when the laser power is 3kW and the scanning speed is 6 mm/s. The microstructure of the cladding layer consists of the dendritic solid solution and the regenerative secondary dendrites. The phases of γ-Ni, Ni4B3, Fe3C, B13C2, Cr3Ni2, （Fe,Ni）23C6, Fe23（C,B）6 and BaC are detected in the coating. The average microhardness of the coating （900 HV0.3） is higher than that of the substrate. Moreover, the wear resistance of the coating is 7.6 times higher than that of the substrate. The improvement in hardness and wear resistance of the coating is attributed to the unmelted B4C particles, the new generated reinforced phases and hard phases.