Portugaliae Electrochimica Acta
versão impressa ISSN 0872-1904
This work aimed to study the corrosion inhibition of carbon steel in 2 M HCl solutions using some aminopyrimidine derivatives. In this investigation the techniques of measurements were: weight loss, linear polarization, impedance and corrosion penetration. The inhibitory effect of the investigated compounds resulted from their adsorption onto the carbon steel. Their adsorption on the metallic surface obeyed Frumkins model of adsorption. The inhibition efficiency of the compound greatly depends on the electron density on the molecules, which in turn depends on its structure. The values of activation energy were determined in 2 M HCl in the absence and in the presence of inhibitors. The presence of inhibitors increases the values of the activation energy of corrosion. The adsorption of these compounds onto the metallic surface occurs via the N-atoms of amino-groups, O-atoms of hydroxy-groups, and S-atoms of mercapto group present in the compound. For this reason the inhibitory effect of the inhibitors varied according to the number and nature of adsorption centers in the molecules.
Palavras-chave : corrosion penetration; carbon steel; aminopyrimidine derivatives; linear polarization; impedance.