中文摘要：

目的通过激光熔覆技术，在Q235钢表面原位生成WC-B4C增强镍基熔覆层。方法以WO3，B2O3，C和Ni60混合粉末为预涂原料，采用激光熔覆技术原位生成WC-B4C增强镍基熔覆层，对熔覆层的显微组织和物相构成进行分析，研究其摩擦磨损性能。结果采用合适的工艺参数，通过原位生成WC—B4C形成的增强镍基涂层形貌良好，与基材呈现较好的冶金结合。熔覆层平均硬度1200HV0．3，摩擦磨损失重仅为纯Ni60熔覆层的1／3。结论熔覆层硬度较高，耐磨性很好。大量原位生成的WC-B4C增强相及其均匀分布是熔覆层硬度和耐磨性提高的原因。

英文摘要：

Objective To in-situ synthesize WC-B4C reinforced Ni-based composite coating on the surface of steel Q235 sub- strate using laser cladding technique. Methods Using WO3 , B2O3 , C and Ni60 as pre-coating raw materials, in-situ WC-B4C rein- forced Ni-based composite coating was synthesized by laser cladding technology. The microstructure observation, component and phases analysis of the coatings were performed to analyze the friction and wear resistance performance. Results The results indica- ted that a good finish WC-B4C particulate reinforced composite coating could be achieved by proper laser cladding processes. The coatings epitaxial growing from the substrate with excellent bonding between the coating and substrate was assured by the strong metallurgical interface. The in situ synthesized WC-BoC particulate reinforced Ni-based composite coating had very high hardness of 1200HV0.3, and excellent wear resistance which was only 1/3 that of pure Ni60 coatings. Conclusion The coating layer had improved hardness and wear resistance, which was due to the in-situ synthesis of WC-BoC and its homogenous distribution in thecladding layer.