Electrochemical and passivation behavior of a corrosion-resistant WC-Ni(W) cemented carbide in synthetic mine water

Two different grades, WC-20 vol.% Ni and Co cemented carbides, respectively were systematically investigated concerning their microstructure, binder composition, corrosion behavior. SEM-EBSD analysis verified that both grades have similar WC grain sizes (0.9–1.1 μm). AES confirmed the phase of respective grade is an alloy Ni-W Co-W concentration W in Ni- Co-binder 21 10 at. %, respectively. In synthetic mine water (SMW), EIS behavior WC-Ni(W) at open circuit potential (OCP) conditions was studied for exposure periods (up to 120 h). The data fitting estimates low capacitance high charge transfer resistance (Rct) values, which indicate passive film formed on thin exhibits resistance. At OCP potentiostatic-passive conditions, SEM investigations confirm uncorroded microstructure WC-Ni(W). AR-XPS studies formation extremely (0.25 nm) WO3 responsible WC-Ni(W), conditions. However, above transpassive potential, instability observed, i.e., corroded morphology grains Ni(W) binder. electrochemical parameters, Rct, current density, density a far better alternative than WC-Co(W) application SMW.