The design of critical components facing a steadily expanding variety of aggressive environments calls for an insightful understanding of hardmetal corrosion mechanism. To this aim, we have investigated the performance of three WC-Co grades, implementing systematic variations of binder content and carbide granulometry, in aqueous sulphate solutions with pH in the range 1-10. Our study is based on a multi-technique approach employing a suite of electrochemical methods: potentiostatic, galvanostatic, potentiodynamic and impedance spectrometry. Our results have been interpreted with a phenomenological model accounting for the impact of material and environmental parameters – the key ones resuting to be pH and binder content - on the pseudopassive behaviour controlling corrosion resistance. Since pseudopassivity crucially depends on the electronic structure of corrosion product films, we have set up a program for their systematic study based on in situ optical and photocurrent measurements: a selection of preliminary results is proposed in this paper.