ABSTRACT

Ni–Cu composite coatings have been fabricated on a 6061 aluminium alloy surface using a pulsed Nd-YAG laser. The basic coating was Ni–Cu powder with a Ni:Cu ratio of 4:1. The effects of adding to this powder 0.9 wt.% CeO₂, 0.9 wt.% Si and 0.9 wt.% Co on the microstructure, microhardness and wear properties of the coatings have been investigated. The results show that, on adding the CeO₂, Si or Co powders, the microstructure of the top region of the coating is mainly composed of equiaxed grains, dendritic crystals and fine equiaxed crystals, whereas the bottom region mainly consists of long rod-like, dendritic crystals and some particles. The average microhardness of the 99.1 wt.% Ni–Cu + 0.9 wt.% CeO₂ coating is 529.05 HV, which was about four times higher than that of the bare 6061 aluminium alloy. In addition, the average friction coefficient decreased on adding CeO₂, Si and Co powder to the Ni–Cu composite coating.

摘要

使用脉冲 Nd-YAG 激光在 6061 铝合金表面上制备了 Ni-Cu 复合涂层。基本涂层是Ni-Cu 粉末，Ni:Cu 的比例为4:1。研究了向该粉末中添加 0.9 wt.% CeO ₂、0.9 wt.% Si 和 0.9 wt.% Co 对涂层的微观结构、显微硬度和磨损性能的影响。结果表明，加入CeO ₂、Si或Co粉末后，涂层顶部区域的显微组织主要由等轴晶粒、树枝状晶体和细小等轴晶体组成，而底部区域主要由长棒状结构组成。 、树枝状晶体和一些颗粒。99.1 wt.% Ni–Cu + 0.9 wt.% CeO ₂的平均显微硬度涂层为 529.05 HV，大约是裸露 6061 铝合金的四倍。此外，在Ni-Cu 复合涂层中加入CeO ₂、Si 和Co 粉末后，平均摩擦系数降低。