Koroziono ponašanje bakra u sulfatnoj sredini u prisustvu organiskih inhibitora

Abstract

Koroziono ponašanje bakra u ovom radu ispitivano je u alkalnoj sulfatnoj sredini u prisustvu potencijalnih inhibitora korozije: purina, cisteina, 2-aminotiazola i 2-amino- 5-etil-1,3,4-tiadiazola. Uticaj purina i cisteina na ponašanje bakra ispitivan je i u neutralnoj sulfatnoj sredini. Rezultati elektrohemijskih ispitivanja pokazali su da sva ispitivana jedinjenja dovode do smanjenja gustine struje što ukazuje na njihovo inhibitorsko dejstvo...

The corrosion behaviour of copper in alkaline sulphate media in the presence of potential corrosion inhibitors: purine, cysteine, 2-aminothiazole and 2-amino-5-ethyl- 1,3,4-thiadiazole was investigated in this study. The effect of purine and cysteine on copper behaviour in neutral sulphate media was studied as well. The results of electrochemical tests have shown that all investigated compounds reduce current density, which indicates their inhibitory characteristics. The inhibition efficiency increases as inhibitor concentration increases, reaching values between 80 #$@% KH%L% #'% #$% !$-!D!'(3% C($C*$'3#'!($% (0% FGFH-2 mol dm-3. The concentration effect becomes especially pronounced as the potential to which the electrode is exposed during chronoamperometric measurements gets higher. The open circuit potential and the corrosion potential are shifted toward more negative values indicating the dominant effect of the inhibitor on the cathode process; however, the shift is not significant, so the inhibitor acts as a mixed type. The exception is observed when cysteine is introduced into alkaline solutions, which results in a significant potential shift toward more negative values. Consequently, it can be said that cysteine has a dominant effect on the cathode process under the said conditions. The inhibitory effect of organic compounds occurs as a result of their interaction with copper surface, including the adsorption of the inhibitor molecules on the surface of copper or the formation of a complex with copper. The adsorption of all the inhibitors studied in this research proceeds according to the Langmuir adsorption isotherm. Based on the established adsorption model, it is possible to calculate the Gibbs free energy of adsorption. The values range from -30 to -40 kJ mol-1, pointing to a spontaneous adsorption that can be characterized as a strong physical adsorption with slight chemisorption.