Stress corrosion cracking (SCC) of AISI 321 (UNS S32100) stainless steel (SS) in 0.5 mol/L sodium chloride (NaCl) +0.5 mol/L hydrochloric acid (HCl) solution and the inhibition effects of some iodides and iodine (I2) were studied using the slow strain rate technique. Iodides studied were tetramethyl ammonium iodide (TMAI), tetrabutyl ammonium iodide (TBAI) and potassium iodide (KI). The additives effectively inhibited SCC of AISI 321 in the solution. Inhibition effects resulted mainly from the role of iodide ion. Electrochemical measurements showed the corrosion current density (Icorr) of the steel increased rapidly and then fluctuated as strain increased. The increase in Icorr was markedly slower in solutions containing I– ions or I2. Inhibition effects of I– ions and I2 on SCC were attributed to the anodic reaction of the corrosion process and reduction of the accelerating effect of strain on Icorr.

Subject
Acid inhibitors, Ions, Corrosion currents, Additives, Sodium chloride, Chloride solutions, Density, Sodium chloride solution, Anodic reactions, Caustic stress corrosion cracking, Cathodic inhibitors, Chloride stress corrosion cracking, Anodic inhibitors
Keywords:
chloride, inhibitor, stainless steel, stress corrosion cracking
NACE International
1993
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