Effect of Cr on the microstructure and properties of TiC-TiB2 particles reinforced Fe-based composite coatings

Fe-Ti-Cr-B-C particles reinforced Fe-based composite coatings were produced by laser cladding. The influence of ferrochromium on the microstructure and properties of the coatings were systematically investigated by optical microscopy (OM), X-ray diffraction (XRD), scanning electron microscope (SEM), and energy dispersive spectrometer (EDS), ring-block wear testing machine and box-type resistance furnace, as well as micro-hardness tester. The results showed that the multiple TiC, TiB2 presented flower-like shape and blocky shape, respectively in the coating. Ferrochromium (FeCr) addition could increase the hardness, wear resistance and the high-temperature oxidation resistance of the coating. As the content of FeCr was 12 wt%, the hardness of the coating reached the highest value, 1027 HV, and the wear resistance was about 3 times the substrate, 2 times the coating without ferrochromium addition. The high-temperature oxidation resistance of the coating with FeCr addition was 3-5 times the substrate. However, while the content of FeCr addition was 18 wt%, some coarse net-like carbides and cracks were found in the coating.