Corrosion inhibition of low carbon steel in HCl by 2-mercapto-5- (2-methoxyethyl)amino-1,3,4-thiadiazole: insights from gravimetric analysis and SEM

The anti-corrosion properties of 2-mercapto-5-(2-methoxyethyl)-amino-1,3,4-thiadiazole (MMAT) for low carbon steel in 1 M HCl was investigated by weight loss measurements and scanning electron microscopy (SEM). As part of the evaluation of performance, the study focused on different parameters that influenced corrosion inhibition such as concentration of MMAT, time of immersion and temperature. The highest inhibition efficiency obtained was on 92.2% at the 0.5 mM MMAT concentration and at the 303 K temperature thus definitively proving the efficiency of the used inhibitor. From the gravimetric analysis it was evidenced that inhibition efficiency increased with increasing immersion time and temperature. A rise of efficiency with temperature and as supported by ΔG0ads values calculated for the reaction that occurred showed that MMAT exhibits both the physical and chemical adsorption on the surface of the steel. The adsorption process can be explained in terms of the Langmuir adsorption isotherm and experimental data backed the process. Based on the SEM analysis, it was established that the formation of MMAT led to the development of a barrier on the surface of steel thus preventing corrosion. This study helps to understand the particulars of MMAT’s corrosion inhibition mechanism because of the detailed examination of these parameters. This research contributes positively to the knowledge of MMAT’s mode of operation in preventing corrosion in acidic environments for future reference. It can be concluded that MMAT is the suitable candidate for further elaboration of corrosion inhibitors, which could be used in different branches of industry where the metal protection is an essential factor.