Effect Of Al Alloy Composition On Physical And Crystallographical Properties Of Plasma Electrolytic Oxidized Coatings I. Physical Properties Of Peo Layer

Physical properties of Plasma electrolytic oxidized 8 different types of Al alloys, A-1100, A-2024, A-5052, A-6061, A-6063, A-7075,ACD-7B and ACD-12 were investigated. The electrolyte for PEO was Na2SiO3 solutions with NaOH and some alkali earthen metal salts. Porous layer near the surface of PEO coating was not found, and surface roughness Ra50 was below 2.5 mu m. Surface roughness was affected by growth rate of plasma electrolytic oxidized layer, not by Si content in Al alloy.