Surface modification of a Mg alloy for wear related applications via cold spray and micro-arc oxidation

Wear performance of AZ31 alloy has been examined after modifying the surfaces through cold spray deposition and micro-arc oxidation. Cold spray deposition of ~240 µm thick, 40 vol. % Al2Zr reinforced Al matrix composite layer and forming a MgO based oxide layer via micro-arc oxidation provided ~3 times and three orders of magnitude reduction in wear rate, respectively. Sequential application of cold spray and micro-arc oxidation favoured an Al2O3 ‒ ZrO2 composite oxide external layer exhibiting enhanced wear performance with that of the MgO based external oxide layer. Additionaly, scratch tests revealed superior mechanical stability of the Al2O3 ‒ ZrO2 composite oxide layer. Reduction of the cold spray layer thickness and its reinforcement percentage to ~70 µm and 20 vol. %, respectively, did not cause remarkable distinction in the mechanical stability of the external composite oxide layer. These findings could be promising from the perspective of sustaining lightweight Mg alloy components, while improving their wear resistance.