Some Schiff-bases and relative amines were tested as copper corrosion inhibitors in aqueous 25 vol.% ethanolic 0.1 M NaCl solutions at 30 °C. Polarization curves and weight-loss measurements allowed the inhibitor efficiencies of the additives to be screened. The data showed a remarkable decrease in the corrosion rate only in the presence of N-2-mercaptophenyl-salycilideneimine (BSS) or 2-mercapto-aniline (AS). Nevertheless, better results were always obtained with the Schiff bases than with the amines. In order to study the nature of the solid product formed in free corrosion conditions or, in the case of BSS, in anodic galvanostatic conditions, their IR spectra were compared with those of the synthetic complexes obtained with these organic substances and copper (I) or copper (II). The surface analysis of the specimens at the end of the immersion tests was carried out using scanning electron spectroscopy and photopotential measurements. Further investigation showed that the inhibition of copper corrosion by BSS and AS followed the Langmuir and the Frumkin adsorption isotherm, respectively, over a wide range of concentrations. The computed adsorption energies together with some tests on the pre-filming action of the two substances indicated chemisorption as the inhibition mechanism.
Innibitive action of some Schiff bases and amines towards the corrosion of copper in an aqueous alcoholic medium.
MONTICELLI, Cecilia;BRUNORO, Giancarlo;FRIGNANI, Alessandro;MARCHI, Andrea
1986
Abstract
Some Schiff-bases and relative amines were tested as copper corrosion inhibitors in aqueous 25 vol.% ethanolic 0.1 M NaCl solutions at 30 °C. Polarization curves and weight-loss measurements allowed the inhibitor efficiencies of the additives to be screened. The data showed a remarkable decrease in the corrosion rate only in the presence of N-2-mercaptophenyl-salycilideneimine (BSS) or 2-mercapto-aniline (AS). Nevertheless, better results were always obtained with the Schiff bases than with the amines. In order to study the nature of the solid product formed in free corrosion conditions or, in the case of BSS, in anodic galvanostatic conditions, their IR spectra were compared with those of the synthetic complexes obtained with these organic substances and copper (I) or copper (II). The surface analysis of the specimens at the end of the immersion tests was carried out using scanning electron spectroscopy and photopotential measurements. Further investigation showed that the inhibition of copper corrosion by BSS and AS followed the Langmuir and the Frumkin adsorption isotherm, respectively, over a wide range of concentrations. The computed adsorption energies together with some tests on the pre-filming action of the two substances indicated chemisorption as the inhibition mechanism.I documenti in SFERA sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
