Effect of Solution Properties on the AC/DC Spark Anodizing of Al-Cu alloy AA2219

An AC/DC spark anodizing method was used to coat an aluminum-copper (Al-Cu) alloy (AA2219) with an oxide film to protect it from corrosion. In this work, anodizing solutions containing 0.15 M KOH and various concentrations of Na2SiO3 have been used. The effect of the electrolyte solution composition and the repeated use of the anodizing solution on the anodizing process and on the oxide film properties have been investigated. Scanning electron microscopy (SEM) and energy dispersive X-Ray (EDX) have been used to characterize the oxide film morphology and composition, respectively. Corrosion assessment was carried out using linear sweep voltammetery (LSV) in borate buffer solution (pH 7).