SCC Susceptibility of Austenite Stainless Steel in MgCl₂ Solutions Containing Silicate Ions

Abstract

In MgCl₂ solutions containing silicate ions, the susceptibility to stress corrosion cracking (SCC) for austenite stainless steel has been investigated by means of electrochemical polarization measurements, impedance measurements, slow strain rate tensile tests (SSRT), and ion transport measurements. It was found that the SCC susceptibility of austenite stainless steel was reduced by adding Mg₂Si₃O₈ in MgCl₂ solutions, and that this is due to the suppression of oxygen reduction reaction by the pH buffering effect of undissolved Mg₂Si₃O₈. Membranes fabricated by pressing Mg₂Si₃O₈ particles showed weak selective anion transport properties, suggesting that Mg₂Si₃O₈ film formed during long immersion period suppresses the penetration of chloride ions to the specimen surface.