Corrosion inhibition effect of 1-thia-3-azaindene on type 304 austenitic stainless steel in 3M H2SO4 solution

Abstract

Abstract Corrosion inhibition of 1-thia-3-azaindene (T3A) on type 304 austenitic stainless steel was studied in 3 M H2SO4 solution at specific concentrations by potentiodynamic polarization. Results showed T3A performed effectively with optimal inhibition efficiency of 92.58% at 1.5% volumetric concentration with the corresponding corrosion rate of the steel at 0.53 mm/y compared to 6.72 mm/y in the acid solution without T3A compound. Inhibition performance increased with inhibitor concentration. T3A exhibited anodic type chemisorption inhibition according Langmuir, Temkin, Frumkin and Freundlich adsorption isotherms with correlation coefficient generally above 0.9. Polarization plots showed significant passivation behaviour after metastable pitting activity before breakdown at pitting potential signifying extensive surface coverage of the steel. The cathodic portion of the polarization plot showed H2 evolution and O2 reaction mechanisms are under activation control.