Evolution of plasma electrolytic oxidation coatings formed on AM50 Mg alloy utilizing various alkaline electrolytes with and without glycerol additive and its corrosion behavior

Abstract

The widespread application for Mg and its alloys are severely restricted mainly due to its relatively low strength and ductility and poor corrosion behaviour, particularly in the aqueous environment. The plasma electrolytic oxidation (PEO) process for improving the corrosion resistance of the Mg-based alloys, has been widely studied/utilized in the research and commercial arena. Until now only a few studies have been carried on the evolution of the PEO coatings over Mg and its alloys and the effect of glycerol as an electrolytic additive on PEO coating evolution has not been investigated till date. Therefore, this study aims to systematically investigate the evolution and electrochemical behavior of the PEO coatings synthesized under similar operating conditions from the silicate-based, phosphate-based, and mixed silicate-phosphate-based alkaline electrolytes (abbreviated as bSi-PEO, bP-PEO, and bm-PEO respectively) as a function of PEO processing time... newline