Erosion–corrosion resistance of a β-Ta₂O₅ nanocrystalline coating in two-phase fluid impingement environments

Abstract

In this study, a β-Ta₂O₅ coating was deposited onto a Ti–6Al–4V substrate using a double-cathode glow discharge plasma technique. The hardness and elastic modulus values of the β-Ta₂O₅ coating were almost 4 times and 1.8 times greater than that of the Ti–6Al–4V substrate, respectively. Potentiodynamic polarisation curves indicated that the current densities of the β-Ta₂O₂ coated sample are least one order of magnitude less than that observed for the uncoated substrate under a solid/liquid slurry flow. Electrochemical impedance spectroscopy results showed that the resistance values for the β-Ta₂O₅ coating are of the order of 10⁶ Ω cm², and at the same erosion time, the resistance value for the β-Ta₂O₅ coating is one order of magnitude greater than that of the Ti–6Al–4V.