Inhibition of corrosion of L 80 alloy in sodium hydroxide solution (pH=12) by succinic acid

Abstract

Inhibition of corrosion of L80 alloy in sodium hydroxide solution (pH=12) by succinic acid has been evaluated by electrochemical studies such as polarization and AC impedance spectra. The study reveals that succinic acid is able to control corrosion of L80 alloy in NaOH solution (pH = 12). When L 80 alloy is immersed in NaOH solution , the linear polarisation resistance (LPR) increases and the corrosion current (Icorr) decreases as revealed by potentiodynamic polarization study. Succinic acid at pH=12 functions as anodic type of inhibitor. When L80 alloy is immersed in NaOH solution , the charge transfer resistance (Rt) increases, impedance increases, phase angle increases and double layer capacitance (Cdl) value decreases . These results suggest that a protective film is formed on the metal surface and probably the protective film consists of Fe 2+ - inhibitor complex (Iron succinate).