Wear and corrosion properties of plasma transferred arc welding Ni-based coatings reinforced with NbC particles

Abstract

The wear resistance and corrosion resistance of Ni-based niobium carbide (NbC) coatings were investigated via scanning electron microscopy (SEM), energy dispersive spectrometry (EDS), X-ray diffraction (XRD), electrochemical polarization, electrochemical impedance spectroscopy (EIS), digital microhardness testing, and wear testing. The results revealed that the substrate was mainly composed of a γ-Cr (Fe) solid solution, and the composite coating was composed of FeNi, NbC, and Ni. Electrochemical test results suggest that the Ni-based coating with a NbC content of 20% has high passivation resistance, low corrosion current, and positive corrosion potential, providing a better protective barrier layer to the AISI 4145H steel against corrosion. In addition, the hardness of the coating increased gradually with increasing NbC content. When the NbC content is 20%, the coefficient of friction (COF) and wear rate of the coating are the lowest, indicating that the coating is more wear resistance than other coatings.