紫铜表面激光熔覆镍基合金的组织与性能

Microstructure and mechanical properties of laser clad Ni-Cr-B-Si coating on copper alloy

利用激光熔覆技术在紫铜表面制备镍基合金涂层。采用SEM、XRD、EDS、显微维氏硬度计进行组织结构和硬度分析,并测试了紫铜基体、镍基熔覆层的耐冲蚀磨损性能。结果表明:激光熔覆层与铜基体形成冶金结合,组织致密、晶粒细小、无裂纹、孔隙、夹杂等缺陷,熔覆层内具有等轴晶、树枝晶及平面晶等不同结构,并有Cr、Ni、B等强化相颗粒。当冲蚀角为60°时紫铜基体和熔覆层的质量损失率都比较大,随着冲蚀时间的增加,熔覆层质量损失率比紫铜的质量损失率要低得多,激光熔覆层的耐磨性比基体组织的耐磨性提高了近3倍,激光熔覆层的耐冲蚀磨损性能得到明显提高。

The Ni-Cr-B-Si coating was clad on copper surface by CO2 laser cladding process. Microstructure and hardness of the clad layer were observed and analyzed by means of SEM, XRD, EDS, and micro-hardometer, and the erosion wear resistance of the coating and the substrate was also tested. The results show that the interface of the coating and substrate is metallurgical bonded, the microstructure is fine and compact, and above all it is crack-free, porosity-free, and slag inclusion free. The laser clad layer consists of equiaxed crystal, branch crystal, plane crystal and strengthening phase particles of Cr, B, Ni phases. Both the mass losses of the clad layer and the substrate are relatively higher when wear test at eroding angle of 60°. With increasing wearing time, the mass loss of the clad coating decreases and is less than that of copper substrate. Erosion wear resistance of the clad layer is obviously enhanced and is three times than that of the substrate.