Evaluation of Electrochemical Corrosion Behavior of WC-Ni-Al and WC-Co Cemented Carbides

WC-Co cemented carbide exhibits remarkable mechanical properties, with applications in several engineering areas. However, its high cost, toxicity, and the search for cemented carbides with greater corrosion resistance have led to a demand for an alternative binder phase. In this study, the corrosion behavior of WC–NiAl cemented carbide (90 wt.% WC, 9.5 wt.% Ni, and 0.5 wt.% Al), processed by conventional powder metallurgy, was compared with that of conventional WC–Co cemented carbide in a 3.5 wt.% NaCl solution. The samples were characterized by scanning electron microscopy, energy-dispersive X-ray spectroscopy, and X-ray diffraction before and after corrosion tests. In the electrochemical tests—open circuit potential, linear potentiodynamic polarization and electrochemical impedance spectroscopy (EIS)—the sample with nickel and aluminum binder exhibited more noble potentials, lower current density values, and higher total impedance than the sample with the cobalt binder.