Effect of Molybdate on Corrosion Performance of Oxide Coating Produced on 7075 Al Alloy Using PEO

In this research, plasma electrolytic oxidation (PEO) coatings were prepared on 7075 Al alloy in a silicate-based solution with Na2MoO4 additive using unipolar waveform at constant current density. The displayed micro-pores, micro-cracks, pancake-like and crater-like features, also solidified molten oxide particles the surface. majorly composed of Al2O3 (γ, δ, α), SiO2 (amorphous), MoO3 phases, which confirms incorporation molybdenum case additive-containing coatings. Molybdenum species transported through cracks, channels, micropores, as ready access pathways into coating partly sealed pores. EIS technique was used to evaluate long-term corrosion performance up 168 h immersion 3.5 wt.% NaCl solution. results showed that barrier action PEO highly enhanced by adding due higher resistance alumina achieved chlorine absorption its stability MoO3. formed presence 5 g L−1 highest thickness lowest porosity percent (15.15%), provided long times.