Corrosion Resistance of Thermal Sprayed Aluminum Coated Steel Exposed to the Atmosphere for 25 Years

Abstract

Thermal sprayed aluminum coated steels were exposed to subtropical climate at the University of the Ryukyus, Okinawa. They were found to exhibit good corrosion resistance even after 25 years. The results of the present study indicate that the thickness of the thermal sprayed aluminum film need not necessarily decrease, rather it may increase with the duration of exposure, but the porosity clearly increased. Furthermore, a film of alumina was formed on the rust where damaged steel was exposed to the atmospheric environment. Therefore, the thermal sprayed aluminum film is believed to provide 1) environment interception and 2) electrolytic protection.