Effect of TiC addition on the microstructure and properties of Ni3Ta-TaC reinforced Ni-based wear-resistant coating

The present study focuses on the surface wear-resistant strengthening technology of the tunnel boring machine disc cutter ring. Ni3Ta-TaC reinforced Ni-based wear-resistant coatings were synthesized in-situ on the surface of 5Cr5MoSiV steel by laser cladding with pure Ni spherical powder, pure Ta spherical powder and Ni coated graphite. To inhibit coating cracking, TiC powder was added to promote the in-situ formation of TaC. The effect of adding TiC on the microstructure and properties of Ni-based wear-resistant coating has been investigated by experiments and first-principles calculation. The results show that Ni3Ta and TaC particles are synthesized in-situ in the coating, and small TaC particles are aggregated around TiC. The orientation relationship of TaC (100)// TiC (100) is confirmed by EBSD and TEM. The properties of interface of TaC (100) and TiC (100) are calculated by the first-principles, showing that the C-Ti and Ta-C interface has high adhesion and good stability. The wear resistance of the two coatings is 4 times higher than that of the substrate. The addition of TiC can effectively inhibit the formation of the lath-shaped Ni3Ta intermetallic compound and cracks, resulting in excellent wear resistance and toughness.