Corrosion Failure Characteristics and Mechanism of Aluminum Alloy Extruded Profiles for Architecture

In view of a large number of failures of aluminum alloy extruded profiles (aluminum alloy profiles) in construction industry, the causes of failures of aluminum alloy profiles were analyzed through the methods of chemical composition analysis, mechanical property testing, metallographic examination and corrosion morphology observation. The results show that the aluminum alloy profiles exposed to a large amount of chlorine-rich substances during use, and chloride ions damaged the oxide film and coating on the surface of aluminum alloy profiles in humid environment. The damaged parts became anodes and formed passivation-activation batteries with other normal parts of the aluminum alloy profiles, resulting in corrosion of the aluminum alloy profiles. In a humid and dry alternating environment, under the condition that the protective film on the surface of the aluminum alloy profile was partially damaged, alkaline substances reacted with the aluminum alloy matrix, and eventually caused the corrosion failure of the aluminum alloy profiles.