Influence of Al-Si alloy microstructure on the corrosion resistance of coatings formed by the microarc oxidation method

Abstract

Abstract. The impact of the high-silicon aluminum alloy initial microstructure on the quality of the coating formed by microarc oxidation (MAO) has been studied. The MAO treatment is applied to AK12D samples in the initial coarse-grained state and after high pressure torsion. The following coating properties are studied: thickness, microhardness, porosity and corrosion resistance. It is established that the MAO layers properties depend on the base microstructure much. High pressure torsion applied to AK12D samples before MAO results in increase of the coating thickness by ∼ 2 times. The microhardness of coatings reduces and their corrosion resistance degrades by ∼ 10 times.