Method for preparing high-purity nano silicon carbide powder by combining microwave heating technology with self-suspension carbon thermal reduction technology

Abstract

The invention discloses a method for preparing high-purity nano silicon carbide powder by combining a microwave heating technology with a self-suspension carbon thermal reduction technology, relates to a preparation method of high-purity nano silicon carbide ceramic powder, and aims to solve the technical problems that the nano silicon carbide powder prepared by the conventional method is low in purity, the particle size is difficult to be lower than 100nm and is not uniform, and the cost is high. The method comprises the following steps: 1, pre-hydrolyzing monoaromatic ring silane, polyaromatic ring silane, straight-chain silane, silicate ester or orthosilicic acid serving as an initial raw material, adding ammonia gas, basic silane or silazane, reacting to prepare wet gel, replacing, aging, and removing a solvent to obtain silicon-carbon composite aerogel; 2, after the surface of the silicon-carbon composite aerogel is subjected to impurity removal and purification, the silicon-carbon composite aerogel is conveyed to a microwave induction graphite tube nest fluidized bed for pyrolysis and carbonization, and nano silicon-carbon-oxygen ceramic powder is obtained; and 3, carrying out carbon thermal reduction in a graphite tube fluidized bed to obtain the high-purity nano silicon carbide powder. The particle size of the powder is 10-800nm, the purity reaches 6N, and the powder can be used in the field of semiconductors.

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