Effect of hexamethylenetetramine as a corrosion inhibitor for copper in bromide medium

Abstract

The electrochemical behaviour of copper in bromide medium in the absence and presence of hexamethylenetetramine (HMTA) was studied using a rotating disk electrode by several techniques. The results showed that HMTA is a corrosion inhibitor for copper in bromide medium containing FE(III) ion or oxygen as oxidants. Corrosion potential measurements and anodic polarization curves indicated that for [HMTA] < 3.0 × 10 −3 M, the oxidation mechanism is reversible while the CuBr n 1− n species are still soluble and it is not affected by the presence of HMTA; for [HMTA] > 3.0 × 10 −3 M, there is an inhibitive action and the anodic process is not diffusion controlled. The passive film was characterized by fluorescence spectroscope as being a Cu(I)-HMTA-Br − complex.