Corrosion Characteristics of Some Aluminum Alloys in Nitric Acid

Abstract

Corrosion characteristics of some commercially pure aluminum alloys (1060, 1100, 3003, and 5052) in different concentrations of nitric acid have been studied at different temperatures. Alloy 3003 exhibits maximum corrosion in all the acid concentrations followed by 5052, 1100, and 1060 alloys. The corrosion rate of aluminum is found to increase and decrease with time in 20 and 70% acid solutions, respectively. In the concentration range of 20–50% of the acid, all the alloys exhibited slightly passivating tendency during the potentiostatic anodic polarization. The breakdown potential of the alloys varies inversely with temperature, whereas an invariable enobling in steady‐state corrosion potential with rise in temperature is noted. The current density required for initiation of passivation, i.e. is related to temperature by