Exploring corrosion inhibition properties of thiadiazol compound for the protection of carbon steel

Abstract

Thiadiazole derivatives have gained much attention as non-volatile, non-flammable, and non-toxic corrosion inhibitors to build an eco-friendly world. However, these derivatives have found limited practical use for their low aqueous solubility and IE. Here, a water-soluble thiadiazole derivative 2-amino-5-(4-nitrophenyl)-1,3,4- thiadiazole (ANPT) has been synthesized, and its corrosion inhibition behavior has been investigated. A facile one-pot synthesis route has been followed for the synthesis. Fourier-transform infrared spectroscopy and nuclear magnetic resonance spectroscopy have been used to confirm the preparation of ANPT. The corrosion inhibition property of ANPT was investigated for carbon steel specimens in aqueous hydrochloric acid as corrosive media. Electrochemical techniques, open circuit potential measurement, potentiodynamic polarization and impedance spectroscopy were used to determine the corrosion IE. Weight-loss measurement was carried out to investigate the practical inhibition situation. Scanning electron microscopic images, before and after the corrosion, were analyzed to observe the changes in surface microstructure during corrosion. The experimental results of electrochemical tests showed that ANPT is a suitable corrosion inhibitor for carbon steel with 56 % corrosion IE against the highly corrosive 0.5 M HCl solution. The maximum IE has been observed at a concentration of 200 ppm. The ANPT protects carbon steel from corrosion by physical adsorption. The high IE was attributed to the blockingof active sites by the adsorption of inhibitor molecules on the carbon steel surface. It covers the carbon steel surface by reducing both cathodic and anodic reactions. It has been observed that the corrosion IE of ANPT can be further improved to 70 % by adding a low concentration of surfactant cetyltrimethyl ammonium bromide. The results of this study are expected to widen the application of thiadiazole derivatives for corrosion inhibition.