Synthesis of refractory metal carbide powders via microwave carbothermal reduction

The synthesis of two refractory metal carbides, titanium carbide (TiC) and tantalum carbide (TaC), has been examined via the carbothermal reduction of the oxides using microwaves as an alternative energy source. Problems with residual oxygen and exaggerated particle growth were encountered with the titanium-based compound which prevented full conversion to the non-oxide form. This was ascribed to the isomorphism of a suboxide with the carbide crystal structure. More success was observed in the case of the tantalum carbide where complete conversion was achieved, as measured by both chemical analysis and X-ray diffraction. Much faster reaction rates were also observed with higher yields being obtained at lower temperatures and in shorter times than can be achieved using conventional heating.