| Abstract Scope |
Hemicarbides, intermediate phases between metals and stoichiometric carbides, exhibit properties attractive for high-temperature and electronic applications. Their performance depends strongly on particle morphology, which influences reactivity, surface area, and integration in devices. This study reports the solvothermal synthesis for obtaining high concentration of tantalum and niobium hemicarbides using lithium and magnesium as solvents, with carbon black and metal chlorides as precursors. Iron and nickel chlorides also were introduced as dopants to control hemicarbide’s morphology. X-ray diffraction confirmed the formation of metal, carbide, and hemicarbide phases. Specifically, lithium’s highly exothermic behavior promoted carbide formation, whereas magnesium, reacting below its self-ignition temperature, favored formation of hemicarbides. The highest hemicarbide yield (55.7% Ta₂C) was achieved at 672 K with excess magnesium. Nickel enhanced shape control, yielding hexagonal crystals, and hexahydrate dopants improved particle dispersion. These findings offer a foundation for tuning hemicarbide synthesis and morphology via solvent and dopant engineering. |