Effect of Plasma Electrolytic Oxidation Process on Corrosion Resistance of Al-Coated AZ61 Magnesium Alloy

Magnesium alloys are extensively utilized in aerospace, aviation, and automotive

sectors due to their low density and high specific strength, which offer significant

advantages for lightweight structural applications. Their low density especially

directs the attention of the aviation sector, where lightness is necessary, to these

alloys. However, one of the disadvantages that restricts their use in the industry is

their low corrosion resistance. In this study, the Plasma Electrolytic Oxidation (PEO)

process was applied in a silicate-based electrolyte to AZ61 magnesium alloy precoated with aluminum using the electric arc spraying technique. To examine the

characteristics of the fabricated coatings, their phase structures, surface features, and

elemental compositions were investigated through XRD, SEM, and EDS analyses.

Corrosion performances of coatings were investigated by potentiodynamic

polarization test in 3.5% NaCl solution. As a result of electrochemical tests,

corrosion current density values for the base sample (AZ61) and PEO coating (AZ61-

PEO) were determined as 36,29 μA. cm−2 and 6,53 μA. cm−2, respectively. The

findings highlight that the Al₂O₃ layer formed following PEO treatment significantly

enhanced the corrosion resistance compared to the base sample.