Silicon carbide obtaining with DC arc-discharge plasma: synthesis, product characterization and purification

Abstract

The paper presents the results of experimental studies on the silicon carbide powder synthesis from charcoal and silicon in plasma of DC low-voltage arc discharge in ambient air. The observed dependencies of the initial mixture composition, arc discharge duration and treatment cycles on the phase composition of synthesized products allow fabrication of the powdery product composed of two phases: graphite and cubic phase of silicon carbide. The powdery product contains crystals that correspond to the morphology of biomorphic wood-derived silicon carbide. The temperature range suitable for synthesis of powdery product with a removal of an excess of free carbon was established by the differential thermal analysis. The synthesis product consists mainly of carbon and silicon, and insignificant amount of impurities contained in the original charcoal. Oxygen is also present in the synthesis product in an amount up to 4.6 at. %, which may indicate the presence of an amorphous silicon oxide layer on the silicon carbide surface. The proposed method finally yielded the silicon carbide based powder with a lattice parameter a = 4.359 Å.