The Effect of Aluminium Oxide on Crevice Corrosion Resistance of Carbon Steel in Concentrated Lithium Bromide Solutions
Atsushi NONAKA, Hidefumi YAMANAKA and Hidemasa NONAKA
Abstract:In order to evaluate the effect of aluminium oxide on crevice corrosion resistance of carbon steel which is used as a regenerator vessel material in the absorption refrigeration cycle, immersion tests and electrochemical measurements of carbon steel in concentrated lithium bromide solutions were carried out. As a result, when there was mill scale on surface of carbon steel and there existed magnetite as impurity in concentrated lithium bromide solution, it was found that addition of aluminium oxide to the solution was very effective to protect crevice corrosion. It was inferred that aluminium oxide dissolved partially in concentrated lithium bromide solution at high temperature, and deposited into the surface oxide film of carbon steel. Therefore, cathodic reaction on the surface of carbon steel was restrained and the potential of carbon steel became less noble than repassivation potential of crevice corrosion. Key Words:Carbon steel, Aluminium oxide, Magnetite, Mill scale, Corrosion inhibitor, Crevice corrosion, Lithium bromide