The Effects of Electrolyte Composition on Formation and Properties of Micro-Arc Oxidation Layer of 6082-T6 Al Alloy

Micro-arc oxidation layer (MAO) was prepared on 6082-T6 Al alloy. The effects of sodium silicate, sodium phosphate, sodium molybdate and sodium tungstate electrolyte on the formation of MAO layer were compared under constant current and constant voltage mode. The hardness, wear resistance and corrosion resistance of MAO layer prepared under different electrolysis systems were tested by Vickers hardness tester, friction and wear tester, electrochemical workstation and natural immersion corrosion test. The experimental results show that: (1) In the constant current mode, the MAO layer prepared by the sodium silicate system has the highest hardness, the best wear resistance and corrosion resistance; (2) In the constant pressure mode, the MAO layer prepared by sodium molybdate system has the highest hardness, the best wear resistance and corrosion resistance. Based on the results of this experimental study, the formation mechanism of MAO layer is further explained, which will lay a solid foundation for the later study of MAO layer.