Effect of Li₂SO₄ in the electrolyte on the characteristics of oxidation films on ZA1Si12 alloy by micro-arc oxidation

Oxidation films were prepared on ZA1Sil2 alloy surfaces by micro-arc oxidation (MAO). The effect of Li₂SO₄ addition into the electrolyte on the performance of the oxidation films was investigated by thickness measurement, scanning electron microscopy (SEM), X-ray diffraction (XRD), and electrochemical test. It is found that the oxidation film thickens and coarsens with increasing Li₂SO₄ content. The results of XRD analysis indicate that the oxidation film is mainly composed of Al₂O₃ phase and mullite phase. Compared with untreated ZA1Sil2 alloy samples, the samples treated by micro-arc oxidation with Li₂SO₄ addition have a better corrosion resistance.