Anodizing of aluminum alloys in chromic acid solutions of different concentrations

Abstract

Investigation of the 3-percent chromic acid anodizing bath showed that the recommended voltage cycle was essential for formation of the best coatings. It was shown that not only could the corrosion-inhibiting properties of the coatings be improved by an increase in concentration of the electrolyte to 5 to 10 percent of chromic acid, but that the cycle could be eliminated, the time decreased, and the anodizing range of voltage and temperature broadened.