Microstructure and properties of laser cladded B4C/TiC/Ni-based composite coating

In order to study the effect of TiC/B4C ceramic particles on the microstructure evolution and microhardness of Ni204-based cladding coating, TiC/B4C/Ni204-based composite coatings were fabricated by laser cladding. The results showed that the TiC ceramic particles in the 30%TiC+70%Ni204 coating do not decompose. TiC is the main reinforcing phase in the coating; however, in 30%B4C + 5%TiC+65%Ni204 composite coating, TiB2 phase was in situ synthesized, and graphite, Fe2B, Ti-Mo-Nb, (Ti, Nb, Mo)(B, C) were formed simultaneously in the coating. The addition of TiC promoted the dissolution and reaction of B4C. In the presence of 30%TiC, the average microhardness and friction coefficient of the coating were 966.4 HV0.5 and 0.198, respectively, which were 3.23 and 0.281 times of the initial Ni204 coating. In the presence of 30%B4C and 5%TiC, the average microhardness and friction coefficient of the coatings were 1308.2HV0.5 and 0.530, respectively, which were 4.38 and 0.752 times of the initial coatings. The enrichment of TiC is proportional to the hardness of the coating.