Absence and presence Organic and Inorganic Inhibitors

Abstract

The aggressive effect of different concentrations of HNO₃ and the inhibitive action of some organic and inorganic additives on the corrosion of copper metal have been studied by thermometric technique. The rate of metal dissolution increases with acid concentration. The copper dissolution rate in 2M HNO₃ was dependent on the chemical properties and concentration of the used additives. The inhibitive action of these compounds obey the Langmuir adsorption isotherm. The degree of surface coverage (?) of adsorbed organic and inorganic additives was determined from the reaction number (R.N.) values. The thermodynamic parameters K_ads. and ?G^?_ads. of organic additives are calculated and illustrated. The values of ?G^?_ads. clear strong physisorption of the tested organic inhibitors on copper metal surface.

Keywords: Copper; Acid Corrosion; Passivity; Thermometry.