A thermodynamical, electrochemical, theoretical and surface investigation of diheteroaryl thioethers as effective corrosion inhibitors for mild steel in 1 M HCl

Abstract

The inhibition effect of three diheteroaryl thioethers (DHATs) namely 5,5'-thiobis (4-phenylthiazol-2amine) (DHAT-1), 4,4'-(5,5'-thiobis(2-aminothiozole-5,4-diyl)) diphenol (DHAT-2) and 4,4'-(5,5'-thiobis(2-aminothiazole-5,4-diyl))bis (benzene-1,3-diol) (DHAT-3) on mild steel corrosion in 1 M HCl was studied by weight loss, electrochemical, scanning electron microscopy (SEM), atomic force microscopy (AFM) and theoretical calculation methods. Among the studied compounds DHAT-3 exhibited maximum inhibition efficiency (η%) of 96.99% at 11.2 × 10-5 mol/L concentration. The potentiodynamic studies revealed that investigated DHATs act as mixed type inhibitors. Adsorption of the DHATs on the mild steel surface in 1 M HCl obeys the Langmuir adsorption isotherm. The results of theoretical calculation, SEM and AFM studies were found to be consistent with the weight loss and electrochemical results. © 2015 Taiwan Institute of Chemical Engineers.