Corrosion and inhibition studies of copper in aqueous solutions of formic acid and acetic acid

• Published in: Corrosion science 1995-09, Vol.37 (9), p.1399-1410
• Main Authors: Singh, V.B., Singh, R.N.
• Format: Article
• Language: English
• Subjects: Applied sciences; Corrosion; Corrosion prevention; Exact sciences and technology; Metals. Metallurgy
• ISSN: 0010-938X; 1879-0496
• DOI: 10.1016/0010-938X(95)00042-I

Corrosion behaviour of copper has been investigated in different compositions of formic acid and acetic acid at 30 °C by a potentiostatic method. The maximum corrosion rate was found in 20–40 mol/o formic acid and in 20 mol/o acetic acid in aqueous solution mixtures. The corrosion rate depended on the concentration of either acid. Formic acid is observed to be more corrosive than acetic acid. The metal exhibited active-passive behaviour in the concentration range of 30–70 mol/o of HCOOH acid in the solution mixture. A short passivity range of potential with a high passivity current density was observed for the metal in the solution mixtures of HCOOH acid while in solution mixtures of acetic acid the metal exhibited only active dissolution. Some organometallic compounds, viz. Bu 2SnCl 2, PhSnCl 3, Ph 2SnCl 2, Ph 3SnCl have been subjected to inhibition studies in the aqueous solution mixture (20 mol/o) of either acid. Among the inhibitors used Ph 3SnCl functions as a better inhibitor in both acids. A strong interaction between the inhibitor and corroding surface of copper is speculated due to adsorption of the inhibitor.