Effects of Ce(SO 4 ) 2 concentration on the properties of micro-arc oxidation coatings on ZL108 aluminum alloys

Abstract Micro-arc oxidation coatings were deposited on ZL108 aluminum alloys in silicate-hydroxide electrolytes containing 0, 0.2, 0.4, 0.6 and 0.8 g/L Ce(SO 4 ) 2 respectively. The oxidation voltages, surface morphologies, phase composition, polarization curves, micro-hardness and thickness of MAO coatings were investigated. With the increasing of Ce(SO 4 ) 2 , the oxidation voltages increased firstly and decreased gradually along with the variation of the coating thickness. The addition of Ce(SO 4 ) 2 could improve the homogeneity and corrosion resistance of the MAO coatings, while the surface micro-hardness increased firstly and decreased finally. There was little influence of Ce(SO 4 ) 2 on the phase composition of MAO coatings.