Electrochemical and theoretical evaluations of 3-(4-chlorophenyl)-7-methyl-5H-[1, 2, 4] triazolo [3,4-b][1,3,4]thiadiazin-6(7H)-one as corrosion inhibitor for copper in nitric acid environment

Abstract

3-(4-chlorophenyl)-7-methyl-5H-[1,2,4]triazolo[3,4-b][1,3,4]thiadiazin-6(7H)-one (CTT) was synthesized and evaluated as corrosion inhibitor for copper in one molar HNO3. The adsorption properties for the synthesized CTT were determined by experimental and theoretical methods in acid environment. The chemical method such as mass loss method (ML), DC potentiodynamic polarization (PDP) and AC impedance (EIS) techniques were utilized to determine the inhibitive behavior of CTT. Outcome data obtained from these methods displayed that with increasing the concentration of CTT its inhibition efficiencies (%IE) increases and reached 91.5% at 24x10-6 M , 25oC using EIS technique. The presence of CTT reduces the capacity of the double layer (Cdl) and improves the charge transfer resistance (Rct) in a solution of one molar nitric acid. CTT is a mixed-type inhibitor from the data obtained from the polarization curves. The attained data indicated that CTT was physically adsorbed onto the Cu surface in accordance for the Langmuir adsorption. The surface protection examination was carried out using scanning electron microscopy (SEM), Energy Dispersive X-ray (EDX) and atomic force microscope (AFM). Also, The quantum chemical parameters of CTT were computed and discussed. The results of several methods are in agreement with each other.

Keywords

• corrosion inhibition, copper, nitric acid, 3-(4-chlorophenyl)-7-methyl-5h-[1,2,4]triazolo[3,4-b][1,3,4]thiadiazin-6(7h)-one (ctt), langmuir isotherm