Performance of alumina coatings prepared by hard anodizing, micro arc oxidation and detonation spray processes on Al-Mg-Si alloy under fretting wear loading

Hard anodizing, micro arc oxidation and detonation spraying of alumina were done on AA 6063 substrate. Fretting wear tests were done at different normal loads and a constant displacement of 55 μm for 50,000 cycles at 5 Hz. The micro arc oxidation and detonation spray coated samples exhibited lower coefficient of friction compared to hard anodizing coated and uncoated samples. Both micro arc oxidation and detonation sprayed samples showed superior fretting wear resistance compared to hard anodizing and uncoated samples. However, hard anodizing coated samples exhibited inferior fretting wear resistance compared to uncoated samples due to cracking and fragmentation of brittle and hard anodized layer. © IMechE 2013 Reprints and permissions: sagepub.co.uk/ journalsPermissions.nav.