Effect of some organic additives on the corrosion behaviour of Cu-Fe and Cu-Al - Fe alloys in sulphuric acid solution

ABSTRACT

The effect of some organic compounds on the corrosion corr behavior of copper - iron alloy [1] and copper - aluminium - iron alloy [II] in 0.5 M H[2]SO[4] aqueous solution was investigated. The techniques of measurements were weight loss, linear polarization and impedance spectroscopy. The organic compounds were glycine [I], alanine [II], valine [III], histidine [IV], 2- aminothiazole [V] and 3- methyl -1- phenyl -2- pyrazolin -5- one [VI]. These compounds have high inhibition efficiency increases according to the order I < II < III < IV < VI < V. The inhibitory effect of these compounds is achieved by their adsorption on the metallic surface via adsorption centers [N - atom and / or S- atom]. Their adsorption the metallic surface follows Temkins' isotherm of adsorption. The values of standard free energy of adsorption, delta G[degree sign] [ads], were calculated from the adsorption isotherms. The negative values of delta G[degree sign] [ads] indicate the adsorption process occurs spontaneously. There is an agreement between the results obtained from the different techniques of measurements