Experimental Modeling of Inhibition's Mechanism of Cupronickel Alloy by DETA and EDA into Acid Corrosive Media

Abstract

The corrosion inhibition of cupronickel alloy in 5% hydrochloric acid (HCl) was investigated in the absence and presence of diethylenetriamine (DETA) and ethylenediamine (EDA) as organic corrosion inhibitors. The effects of inhibitor concentration and temperature were investigated using mass loss method. The results obtained show that EDA act as an anticorrosion material for cupronickel alloy in hydrochloric acid with a maximum performance of 66.7%, while DETA was a poor inhibitor with maximum efficiency of 34.7%. The inhibition performance was found to increase with increase in inhibitor concentration and decrease with increase in temperature. The adsorption of both inhibitors on surface of metal was found to obey Freundlich isotherm. The values of the free energy of adsorption were below − 20 kJ/mol that is indicative of physisorption (physical adsorption). The proposed mechanism of the inhibition process suggests an adsorption of amine groups on metal surface. Mathematical models were also suggested to correlate the dissolution rate data as a function of temperature and inhibitor concentration. High correlation coefficients were obtained between experimental and predicted data. The mean value of residual between the experimental and predicted data was 0.457.