Influence of Na2MoO4 Additive on the Corrosion Resistance of Micro-Arc Oxidation Coatings on 6061 Aluminum Alloy

Aluminum alloys are indispensable in industrial applications due to their excellent mechanical properties, but they are prone to corrosion in humid environments. Micro-arc oxidation (MAO) technology can form a ceramic-like oxide layer on their surface, significantly enhancing corrosion resistance and other properties. This study used aluminum alloys as substrates, added sodium molybdate to a silicate electrolyte, and prepared MAO/ Na2MoO4 composite films using a constant-voltage mode. Optimized process parameters were determined as: current 2A, positive voltage +400V, negative voltage -50V, frequency 500Hz, time 10min, duty cycle 30% (1:1). The electrolyte composition was 20g/L Na2SiO3, 4 g/L Na2MoO4 , 2g/L NaOH, and 1g/L NaF. Electrochemical testing demonstrated enhanced corrosion resistance, with no corrosion observed after 600 hours of salt spray testing. This research provides theoretical foundations and technical support for surface protection of alloy materials.