Silicon carbide was synthesized from mixtures of SiO₂ and graphite by applying the concept of the FFC-Cambridge process and several fundamental aspects of the synthesis route were investigated. Porous disks composed of powders of SiO₂ and graphite in molar ratios of 1:0.5, 1:1 and 1:1.5 were prepared by sintering in inert atmosphere and subjected to electro-deoxidation in molten CaCl₂ at 1173 K under a range of experimental conditions. Disks of molar ratio 1:1.5, reduced at an applied voltage of 2.8 V for a duration of 6 h, yielded exclusively phase-pure SiC of nanowire morphology as the reaction product, while the other precursor compositions provided significant amounts of calcium silicides. Voltages lower than 2.8 V gave mixtures of SiC with elemental Si and graphite, and voltages higher than that gave CaSi alone. Shorter electro-deoxidation times led to incomplete reduction and allowed for the identification of CaSiO₃ as a transient phase. Based on the experimental results a multipath reaction mechanism is proposed, consisting of the electrochemical reduction of SiO₂ and CaSiO₃ to Si and the subsequent in-situ carbonization of the Si formed to SiC. The effect of N₂ at high temperature on the electrochemically synthesized SiC was investigated and the formation of nanowire Si₂N₂O was observed. Overall, the process presented is a facile single-step and low-temperature method for the synthesis of SiC with possible commercial prospects.

Nano-sized powders of the Ta _1−x Hf _x C class of ceramics, with compositions of Ta _0.2 Hf _0.8 C, Ta _0.5 Hf _0.5 C and Ta _0.8 Hf _0.2 C, were successfully synthesized from mixtures of the corresponding metal oxides and graphite by electro-deoxidation in molten CaCl ₂ at 1173 K. X-ray diffraction revealed that the as-prepared Ta _0.8 Hf _0.2 C mixed carbide had a single-phase cubic structure whereas Ta _0.5 Hf _0.5 C and Ta _0.2 Hf _0.8 C had dual-phase cubic structures, indicating that the large proportion of Ta promoted the formation of a homogeneous solid solution of TaC and HfC during synthesis. Electron microscopy proved that the particle size of the mixed carbides was in the nano range, while energy-dispersive X-ray spectroscopy and X-ray photoelectron spectroscopy confirmed that the intended compositions had been attained. Notably, the electrochemical method of synthesizing Ta _1−x Hf _x C mixed carbides proceeds at a significantly lower temperature than the conventional preparation methods. This offers a number of key advantages in that it saves energy, gives better control over composition and allows for higher purity, and it suppresses in situ sintering and thus enables the formation of nanoparticles.