Synthesis and characterization of ultrafine Co–30 wt.%NbC composite powder with a core/rim structure

Ultrafine Co–30 wt.%NbC composite powder with a core/rim structure was synthesized via a direct reduction and carbonization process at 950 °C for 2 h under a vacuum condition. Results show that the particle size of the composite powder is about 150–200 nm. The size of a NbC core is about 110–140 nm and the thickness of its rim is 30 nm approximately. Comparative experiments and thermodynamic calculations indicate that the carbothermal process was greatly improved by the participation of Co3O4 in the raw material.