“…Plasma electrolytic oxidation (PEO, also called micro-arc oxidation) technology is widely used to prepare oxide ceramic films on Al, Mg, Ti, Zr, and their alloys to enhance the wear resistance, corrosion resistance, biocompatibility, and photocatalytic performance [14][15][16][17][18]. It is a plasma electrolysis process under atmospheric pressure in the ambient aqueous solution, where plasma is sustained by a continuous discharge near the electrode after the dielectric layer is broken down under critical voltage [19,20].…”