Abstract:
The nickel (Ni) nanoparticles were deposited on the surface of titanium carbide (TiC) powders by the impregnation-fluidized bed reduction process. The highly uniform Ni coated TiC powders were prepared through the nickel-catalyzed autocatalytic electroless plating reaction. The TiC–Ni cermets were subsequently fabricated by vacuum sintering. The microstructure and phase component of the Ni coated TiC powders and TiC–Ni cermets were characterized by scanning electron microscopy and X-ray diffraction. The performances of the TiC–Ni cermets using the Ni coated TiC powders and the mixed powders under the same sintering conditions were conducted. The results show that the Ni particles are uniformly deposited on the TiC powder surface. Compared with Ni catalyst content (mass fraction), Ni particle size dominates the electroless rate of Ni in electroless plating, with smaller Ni particles yielding higher deposition rates. When the Ni catalyst content is 0.2%, the average Ni particle size is approximately 22 nm, achieving a maximum electroless plating rate of 3.56 mg·g
−1·min
−1. Based on this, the highly uniform TiC–20Ni coated powders (Ni mass fraction is 20%) are prepared, and the TiC–20Ni coated sintered samples achieve the relative density of 99.54% at
1410 ℃. Compared to the cermets fabricated by mixed powders, the homogeneous Ni distribution in the coated powders not only prevents the formation of “Ni pools” in the sintered structure, but also effectively suppresses the high-temperature coalescence and grain growth caused by the direct TiC contact. As a result, the sintered samples fabricated by the coated powders exhibit the superior mechanical properties, including Vickers hardness of HV1.0 (
2214±68) and transverse rupture strength of (
1152±20) MPa.