4-{[4-(Dimethylamino)benzylidene]amino}-5-methyl-4H-1,2,4-triazole-3-thiol as Corrosion Inhibitor for 316 Stainless Steel in 2.5 M Sulphuric Acid: An Experimental and Theoretical Investigation

N. Shet1, R. Nazareth1, P. Krishna Murthy2, and P.A. Suchetan3,*,

1Department of Chemistry, St. Aloysius College, Mangaluru-575003, India

2Department of Chemistry, Bapatla Engineering College (Autonomous), Acharaya Nagarjuna University Post Graduate Research Centre, Bapatla-522102, India

3Department of Studies and Research in Chemistry, University College of Science, Tumkur University, Tumkur-572103, India

*Corresponding author: E-mail: pasuchetan@gmail.com


The corrosion inhibition competence of 4-{[4-(dimethylamino)benzylidene]amino}-5-methyl-4H-1,2,4-triazole-3-thiol (DBTT) on 316 stainless steel (316 SS) in 2.5 M H2SO4 was studied using various electrochemical as well as weight-loss measurements. The alloy surface was examined by scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDX). Concentration effect on inhibition efficiency was investigated by varying concentration from 5 to 2000 ppm in the temperature range 30-60 °C. Results indicated mixed-type inhibitory action of DBTT. The efficiency increased with the raise in concentration of DBTT and temperature, reaching a highest of 92.4 % at 60 °C. Langmuir adsorption isotherm is obeyed. Calculation of different thermodynamic factors suggests that the adsorption is via both physisorption and chemisorption. In addition to these, several global reactivity parameters were calculated using DFT method at B3LYP/6-311++(d,p) basis set. Theoretical calculations are in good concurrence with the experimental results.


316 Stainless steel, Sulphuric acid, Schiff base, Weight-loss method, Potentiodynamic Polarization, EIS, DFT calculations.

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