Corrosion and inhibition of stainless steel pitting corrosion in alkaline medium and the effect of Cl − and Br − anions

• Published in: Applied surface science Vol. 242; no. 1; pp. 114 - 120
• Main Authors: Refaey, S.A.M., Taha, F., El-Malak, A.M. Abd
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 31.03.2005; Elsevier Science
• Subjects: 304L and 316L stainless steels; Applied sciences; Chloride and bromide; Corrosion; Corrosion tests; Exact sciences and technology; Metals. Metallurgy; Sodium carbonate; Chloride and bromide; Sodium carbonate; Corrosion; 304L and 316L stainless steels; Scanning electron microscopy; Potentiodynamic method; Pitting corrosion; Stainless steel; Pitting potential; Carbonates; Corrosion inhibition
• ISSN: 0169-4332; 1873-5584
• DOI: 10.1016/j.apsusc.2004.08.003

The effect of carbonate anion on the pitting corrosion and inhibition behavior of stainless steel samples (304L SS and 316L SS) has been studied using potentiodynamic and scanning electron microscope (SEM) techniques. The effect of concentration of CO 3 2− ions, pH, potential scanning rate and the composition of stainless steel are discussed. Additions of Cl − and Br − ions into the carbonate solution increase the anodic dissolution of stainless steel and decrease its pitting corrosion resistance. The effect of CO 3 2− anion on the inhibition of chloride and bromide pitting corrosion of the two stainless steel types has been studied also. Pitting corrosion decrease with the increasing of sodium carbonate concentration, i.e. increases the resistance of stainless steels towards the chloride and bromide pitting corrosion. This inhibition effect argued to formation of [Fe,Cr]CO 3 film caused by preferential adsorption of the CO 3 2− ion, leading to instantaneous repair of weak sites for pit nucleation.