Effect of Anodization on the corrosion behavior of Aluminium Alloy in HCl acid and NaOH

The effect of anodic oxidation on the corrosion behaviour of Aluminium alloy ‘7075’ in two different media was investigated. The weight loss technique was used to determine the corrosion rate in 1.0M HCl and 1.0M NaOH solutions. These specimens were allowed to stay in the solutions for 504 hours with an interval of 72 hours weight loss measurement. The results shows that in both media, the normal corrosion rate profile of an initial steep rise in corrosion followed by subsequent fall was observed for both anodized and unanodized specimens but with severe attack on those specimens in 1.0M HCl. The anodized Al-Alloys in both solutions have lesser corrosion rate as compared to the unanodized Alloys. It was concluded that, Aluminium Alloy ‘7075’ corrodes faster in 1.0M HCl than in 1.0M NaOH solution and that anodizing helps to reduce the corrosion rate of Al- Alloy in both media.