Chemically-assisted combustion synthesis of silicon carbide from elemental powders

The feasibility of synthesizing submicron silicon carbide from elemental silicon and carbon powders by chemically-assisted self-propagating high-temperature synthesis has been demonstrated. The effect of carbon powder properties, initial concentration of potassium chlorate as an reactive additive, gas atmosphere, and operating pressure on combustion front characteristics, product morphology and its purity as well as phase composition has been studied in detail. It has been found that combustion synthesis of silicon carbide can be accomplished both in nitrogen or argon atmosphere. It has been shown that a formation of silicon carbide at elevated nitrogen pressures is possible when carbon powder with a very high specific surface area is used. Average particle size of silicon carbide synthesized from high purity silicon and carbon powders in a presence of potassium chlorate at elevated nitrogen and argon pressures (P > 0.3 MPa) is approximately 200 nm.