激光熔覆ZrB2-SiC增强Cu基复合涂层的微观结构与摩擦学性能

Microstructure and tribological properties of laser cladding ZrB2-SiC reinforced Cu matrix composite coating

摘要:

为了提高铜表面的强度和耐磨性，以复合粉末（Zr、Si、Ni包B4C、Cu）为原料，采用激光辅助原位合成技术，在纯铜基体表面制备了ZrB2-SiC/Cu复合涂层。通过XRD、SEM和TEM分析了复合涂层的表面形貌、微观结构、相组成和界面结合，并测试了不同增强相含量熔覆层的硬度和摩擦学性能。结果表明：通过设计的原位化学反应成功在铜基体内合成了微米级针状ZrB2和纳米级颗粒状SiC。增强相均与基体形成了清洁、无杂相的界面。两种不同维度与尺寸的增强体，通过多种强化机制，显著改善了复合涂层的力学性能；通过调整激光工艺参数可实现增强体尺寸的控制，随着增强相含量的提高，复合涂层的平均硬度和耐磨损性逐渐增加。当增强相含量为30 wt%时，复合涂层的平均硬度为309 HV0.2，约为纯铜的5.6倍。30 wt%涂层的载流磨损率与含量为10 wt%的涂层相比，降低了约80%。较高含量的复合涂层表现出优异的摩擦学性能。

Abstract:

In order to improve the strength and wear resistance of the copper, ZrB2-SiC/Cu composite coating was prepared on the surface of a copper substrate by laser cladding with the raw materials of Zr, Si, Ni-B4C, Cu composite powders. The surface morphology, microstructure, phase composition and interface combination of the composite coating were analyzed by OM, XRD, SEM and TEM, And the hardness and wear resistance of coatings with different reinforcement phase content were tested. The results showed that the micron-sized needle-like ZrB2 and nano-sized granular SiC were successfully synthesized in the copper matrix by the designed in-situ synthesis reaction. A clean and impurity-free interface formed between the reinforcements and the copper matrix. Mechanical properties of the composite coating were improved by two reinforcements with different dimensions and sizes through a variety of strengthening mechanisms. The size of the reinforcement could be controlled by adjusting the laser process parameters, with the content of the reinforcements increased, the average hardness and wear resistance of the composite coating gradually increased. The average hardness of the composite coating with the reinforcing phase content of 30 wt% was 309 HV0.2, which was about 5.6 times that of pure copper. The current-carrying wear rate of the 30 wt% composite coating was about 80% lower than that of the 10 wt% coating. The higher content of the composite coating showed excellent current-carrying wear resistance.