Corrosion resistance of WC hardmetals with different Co and Ni-based binders

In this work, industrially relevant WC composites with alternative binders (Ni, CoNi, NiCr, CoCr, CoNiCr and NiCrMo) were produced and their corrosion resistance in 0.5 M NaCl was compared to conventional WC-Co system. The main objective is to develop hardmetals with higher corrosion resistance to extend the lifetime of tools and equipment, reducing the demand for new parts and maintenance, thus decreasing the total cost of the operation. The study includes different electrochemical techniques, namely corrosion potential monitoring, Electrochemical Impedance Spectroscopy (EIS) and polarization curves. The purpose is to evaluate the influence of each element on the corrosion resistance of the composites produced. • Several hardmetal composites with multicomponent binders were tested. • Ni based composites presented higher corrosion resistance than the Co based ones. • Cr enhanced the corrosion resistance of Ni-containing composites. • The addition of Mo to WC-NiCr further improved the corrosion resistance. • Corrosion evolved with binder dissolution underneath the surface.