Effect of molybdenum on the high-temperature properties of TiC-TiB2 reinforced Fe-based composite laser cladding coatings

Fe-Ti-B-Cr-Mo-C composite coatings with different molybdenum (Mo) content were in-situ fabricated on a 5CrNiMo die steel substrate by laser cladding. Effects of Mo on the microstructure and high -temperature properties of coatings were investigated by scanning electron microscopy (SEM), X-ray diffraction (XRD), high-temperature oxidation and high-temperature wear resistance test. Results showed that block-like or cuboidal TiB2 and Mo2B, as well as flower-like (Ti,Mo)C reinforced particles have been formed in the coatings. Amounts of martensite in the coating increased with the increasing of Mo. However, cracks are found in the coating while the addition of FeMo70 exceeded 9 wt%. Mo improved the high-temperature oxidation resistance and reduced oxidation rate. Besides, the coatings processed the better high-temperature wear resistance with 9 wt% FeMo70.