Study on microarc oxidation of AZ31B magnesium alloy in alkaline metal silicate solution

The effects of pulsating current and voltage sources with different magnitudes on an oxide film formed by microarc oxidation (MAO) of AZ31B magnesium alloy in alkaline metal silicate solution were investigated. The thickness of an oxide film increased with increasing current source but the uniformity of the surface of an oxide film became worse. The unstable oxidation process represented by fluctuating voltage established across an oxide film was discussed and related to the surface roughness and the melting down of magnesium alloy. By comparing the surface of an oxide film a pulsating current source produced more uniform oxide film on magnesium alloy than a pulsating voltage source.