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 HV_0.5 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 1308.2HV_0.5 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.