Chromium carbide/Fe-based self-fluxing alloy composite coatings produced by vacuum reactive braze coating

Using carbon, iron, silicon, ferrochromium, ferrotitanium and nickel powder as the raw materials, chromium carbide/Fe-based composite coatings with an even and smooth surface were prepared by vacuum reactive braze coating, which combined with a mild steel substrate by a metallurgical bonding. The phase structure, composition distribution and hardness distribution of the coatings were studied by means of scanning electron microscopy (SEM), energy dispersive spectrum (EDS), X-ray diffraction (XRD) and microhardness testing. The results showed that the coating had a composite structure, and the microstructure of the coating consists of an Fe-Ni solid solution matrix and in-situ synthesized hexagon prismy Cr₃C₂. There was a transition zone between the coating and the substrate, in which chemical elements and microhardness had a gradient distribution. The surface hardness of the composite coating was high up to 85HR15N.