“…These coatings are fabricated by different techniques such as oxidation of the metal surfaces [3,[20][21][22], sol-gel process [19], vapor phase deposition [23,24], electrophoresis [25], and thermal spray [26,27]. To improve wear, corrosion and photocatalytic properties of valve metals including Al [7,28,29], Ti [4,[30][31][32][33], Mg [1,[34][35][36][37], and Zr [38][39][40], surface oxidation techniques, such as Micro Arc Oxidation have been successfully used. Micro Arc Oxidation (MAO) process [41][42][43] is a relatively new method to oxidize metallic surfaces which has attracted many research works in recent years.…”