An in-situ FT-IR investigation of the anodic behaviour of WC-Co hardmetal

摘要

An in-situ FT-IR spectroelectrochemical and voltammetric study of the corrosion of a WC-Co hardmetal grade is reported in this communication. A slightly acidic sulphate solution is considered. The potential- and time-dependent anodic formation of CO{sub}2 and Co(OH){sub}2 can be followed with the variation of the vibrational spectra. The formation of CO{sub}2 occurs at the same potential at which tungsten oxidation starts to be detected and the breakdown of passivity can be observed by electrochemical methods. Our results suggest that a threshold potential exists for the oxidation of WC in WC-Co, giving rise to the concomitant oxidation of tungsten and carbon at more noble potentials than those typical for the oxidation of the individual elements.