Microstructure and Wear Behavior of Laser Cladded CoCrNiMox Coatings on the Low Carbon Steel

Abstract

In this study, CoCrNiMox (x = 0, 1, 3 and 5, wt.%) alloy coatings were fabricated on the surface of low carbon steel by laser surface cladding. The scanning electron microscope (SEM), energy dispersive spectrometer (EDS), and X-ray diffraction (XRD) were used to analyze the microstructure and phases of the prepared coatings. The microhardness and wear resistance of these coating were also evaluated. The results showeded that a single-phase face-centered cubic (FCC) structure generated by the CoCrNi ternary compound in all the coatings, the σ phase, and the Mu (μ) phase, enriched with Cr and Mo and originated with additional Mo, exhibited a lamellar structure. The content of FCC single-phase structure in the coating gradually decreases with the increasing of Mo because the addition of Mo can promote the precipitation of the σ phase and the μ phase. Among all the laser cladded coatings, the CoCrNiMo5 alloy coating shows the best properties, owing to the higher proportion of intermetallic compounds in the σ phase and the μ phase, which can provide enhanced performance. This exhibited the narrowest wear scar width and showed the fatigue wear mechanism.