Electroless Cu plating on the microstructure and hardness of Al-Cu powder metallurgy alloy

Oxide film and agglomeration are two obstacles against the property improvement of the Al-based powder metallurgy (P/M) alloy. In the work, the aluminum powders treated by the electroless Cu plating were processed by powder metallurgy technology. X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM) coupled with energy dispersive spectroscopy (EDS) were used to investigate the phase, microstructure and composition of the Cu-plated aluminium powder and the sintered bulks. For comparison, the P/M Al-Cu alloy were also prepared from the premixed powders by the traditional mixing processing. The results show that the electroless Cu plating can eliminate the agglomeration of copper in the sintered compact. The removal of the oxide film via the electroless plating provides more effective surface contact than could be obtained by the conventional process. A CuAl2 phase with a network structure formed in the sintering process. This phase contributed to the uniform microstructure and hardness improvement.