Effect of Electrolyte on Micro Arc Oxidation Coating of Al-2014 Alloy

Micro Arc Oxidation (MAO) coating was performed on Al-2014 aluminium alloy in aqueous solution of silicate, phosphate and hybrid electrolytic environments. The MAO thickness was measured around 5-15 μm, in which significant thickness of both dense and porous layers were identified. A combination of nanocrystalline α-Al2O3and Υ-Al2O3 was identified in the MAO coating using X-ray diffraction analysis. The thickness and morphology of the coating, which is analyzed using SEM are different for different MAO process parameters and it was found that the MAO coating prepared in phosphate electrolyte is giving a better coating with higher coating thickness, minor pore size and better adherence.