Microstructure, Tribological, and Electrochemical Characterization of Hardfacing WC-Ni-Cr on AISI 1045 Carbon Steel Alloy

The present work aims to study the effect of WC-Ni-Cr hardfacing on the mechanical properties and corrosion behavior of AISI 1045 type substrate alloy steel. The hardfacing coatings were obtained by the oxy-acetylene process with and without C-Mo-Al-Ni interlayer. The WC-Ni-Cr hardfacing samples were characterized by scanning electron microscopy coupled with energy-dispersive spectroscopy-ray diffraction, microhardness measurements, 2D-surface roughness, ball-on-disk wear as well as electrochemical analysis. The obtained results show that the hardfacing coatings correspond to a tungsten carbide complex which consists of WC, W2C, Fe6W6C and Fe3Ni phases of 1000-1250 HV hardness and WC particles were distributed homogeneously in Ni-Cr matrix. The wear rate of WC-Ni-Cr hardfacing was reduced significantly by 10 times less than WC-Ni coating under the same condition. On the other hand, porosities and microcracks were observed more in the samples with an interlayer compared to coatings without an interlayer. The obtained result showed that WC-Ni-Cr improved the protection against corrosion for the substrate steel. The present study deduced that the protected steel samples by hardfacing without an interlayer resisted better than those having an interlayer.