Azole Compounds as Corrosion Inhibitors: Part I

ERGUN Ü., EMREGÜL K. C.

JOURNAL OF MATERIALS ENGINEERING AND PERFORMANCE, vol.23, no.1, pp.213-221, 2014 (SCI-Expanded) identifier identifier

  • Publication Type: Article / Article
  • Volume: 23 Issue: 1
  • Publication Date: 2014
  • Doi Number: 10.1007/s11665-013-0737-2
  • Journal Name: JOURNAL OF MATERIALS ENGINEERING AND PERFORMANCE
  • Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus
  • Page Numbers: pp.213-221
  • Keywords: impedance spectroscopy, inhibitor, mild steel, quantum chemical, Schiff base, Tafel, BOILING HYDROCHLORIC-ACID, SCHIFF-BASE COMPOUNDS, MILD-STEEL, MOLECULAR-STRUCTURE, IRON CORROSION, HCL, DERIVATIVES, MEDIA, SURFACTANTS, PERMEATION
  • Ankara University Affiliated: Yes

Abstract

The inhibitory effect of 3-amino-1,2,4 triazole (I), 2-aminothiazole (II), and 3-amino-5-mercapto-1,2,4 triazole (III) on the corrosion of steel in 2 M HCl solution has been studied using chemical technique and electrochemical techniques. The inhibition efficiencies (eta) obtained from all the methods employed are in good agreement. Results reveal compound (III) to be the most efficient inhibitor with an inhibition efficiency of 91%. The inhibition efficiency increases with increasing concentration in all three compounds. Studies clearly indicate that these compounds act as a mixed type inhibitor without altering the cathodic reaction. The inhibitors are adsorbed on the surface according to the Langmuir adsorption isotherm. Quantum chemical parameters such as highest occupied molecular orbital energy (E (HOMO)), lowest unoccupied molecular orbital energy (E (LUMO)), energy gap (Delta E), and dipole moment (mu) have been calculated for 3-amino-1,2,4 triazole (I), 2-aminothiazole (II), and 3-amino-5-mercapto-1,2,4 triazole (III) using semi-empirical PM3 and 6-311G(d,p) DFT methods.