Influence of prior corrosion on the high cycle fatigue behavior of microarc oxidation coated 6061-T6 Aluminum alloy

The objective of this study is to evaluate the influence of prior immersion of microarc oxidation coated and uncoated Al alloy in 3.5% NaCl solution up to 168 h on their high cycle fatigue behavior. The prior immersion caused pitting on uncoated Al alloy while in the case of MAO coated Al alloy no pits were observed. Electrochemical impedance spectroscopy revealed progressive degradation of the MAO coated Al alloy with increasing duration of immersion. The fatigue life of MAO coated Al alloy decreased with increasing duration of immersion but at a significantly lower rate than in the case of the uncoated Al alloy. Thus, MAO coatings provided a measure of protection under corrosion fatigue conditions as compared to the uncoated Al alloy.