Two-step synthesis of TiC0.7N0.3@WC-MoC2 core-shell microspheres and fabrication of TiC0.7N0.3@WC-MoC2-based cermets by SPS

The precursor with TiC_0.7N_0.3@WO₃-MO₃ microspheres were prepared by a novel method from the WO₃-MoO₃ sol dipping. Subsequently, TiC_0.7N_0.3@WC-MoC₂ core-shell structural microspheres were successfully obtained by carburizing the precursor at 900 °C in a flowing mixture of CH4 (20 ml · min⁻¹) and H₂ (200 ml · min⁻¹) for 2 h. Then TiC_0.7N_0.3@WC-MoC₂-15Co cermets were prepared utilizing the core-shell powders by spark plasma sintering (SPS). Powders of the precursors with TiC_0.7N_0.3@WO₃-MO₃ microspheres, TiC_0.7N_0.3@WC-MoC₂ microspheres and TiC_0.7N_0.3@WC-MoC₂-15Co cermets were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM) and X-ray diffraction (XRD). The obtained TiC_0.7N_0.3@WC-MoC₂ microspheres have a dense WC-MoC₂ coatings shell. The thickness of the shell could be easily controlled by adjusting the number of sol dipping cycles. It was found that the TiC0.7N_0.3@WC-MoC₂ microspheres were more beneficial to fabricate the “core-rim” structures by SPS.