Characterization of MAO + Cu Composite Coatings on Aluminum Alloy
Shangkun Wu, Wei Yang, Wei Gao, Yuhong Yao, Yong Zhang, Jian Chen
Abstract
Novel composite coatings were fabricated on 6061 aluminum alloy substrates by two steps combining micro-arc oxidation (MAO) plus electroless copper plating (Cu). Different MAO + Cu composite coatings were compared. Cu continuously and evenly covered an aluminum oxide surface during processing thus changing the surface topography. The adhesion of MAO + Cu composite coating was tested by the pull-out method. The best adhesion strength of the composite coating can reach industrial requirements. The effects of the composite coatings on friction were investigated using a ball-on-disc test method. It is found that copper in composite coatings plays a lubricating effect during the wear process under dry sliding. Furthermore, the mechanisms by which the observed advantages were produced are discussed.