Investigation of in-situ synthesized WC-Ni coating with TiC as heterogeneous nucleation site: First-principles calculation and experimental research

[Display omitted] •Graphite and tungsten powders are completely synthesized into WC during laser cladding.•The nucleation interface of WC/TiC has been investigated using first-principles calculations.•TiC as heterogeneous nucleating agent can significantly improve the nucleation rate of WC.•A high content of fine in-situ synthesized WC composite coating was prepared. To overcome the issue of coarse grains and low synthetic content of in-situ synthesized WC due to its low nucleation drive, TiC was used as nucleating agent to promote the nucleation of WC during laser cladding. The interfacial energy and electronic structure of the heterogeneous nucleation interface were investigated by first-principles calculations. The calculated results show that TiC(111) surfaces are good heterogeneous nucleation interfaces for WC because they can form a co-lattice interface with a lattice mismatch of 4.6 % and have a high adhesion work (Wad) and a low interfacial energy (γ), e.g., the W-WC(0001)/C-TiC(111)-HCP1 interface exhibits a Wad of 9.78 J m−2 and a γ of 1.86 ∼ 1.89 J m−2 and the W-WC(0001)/Ti-TiC(111)-HCP1 interface exhibits a Wad of 5.38 J m-2 and a γ of 1.02 ∼ 1.62 J m−2. The experimental results confirm that TiC is an effective nucleating agent to promote the nucleation of WC. The content of the WC increases from 34.96 % to 66.80 % and the grain size of the WC is refined from 13.37 nm to 3.53 nm after the pre-addition of 2 wt% TiC.