Preparation method of pressureless-sintered silicon carbide gel

Abstract

The invention discloses a preparation method of pressureless-sintered silicon carbide gel. The preparation method comprises the following steps: 1) treating a main material including SiC particles and B4C particles into a finished thick liquid product, wherein the B4C particles are taken as a sintering aid, the particle size of each SiC particle is no more than 0.8 mum and the particle size of each B4C particle is 3.2 mum; 2) adding auxiliary materials into the finished thick liquid product obtained in the step 1) to prepare a thick liquid before casting while performing stirring, wherein the auxiliary materials comprise acrylamide, N,N'-methylenebisacrylamide and ammonium polyacrylate; 3) performing die casting, adding ammonium persulfate in the thick liquid before casting, performing uniform stirring and secondary die casting, and performing demoulding to prepare a blank; and 4) performing dehydration, degreasing and sintering. In the scheme, SiC particles with relatively small particle size are taken as a main gel material and B4C particles with relatively large particle size are taken as a sintering auxiliary agent and a framework material, thereby preparing the silicon carbide gel with high quality.

Description

technical field [0001] The invention relates to the preparation of a porous silicon carbide material, in particular to a method for preparing a pressureless sintered silicon carbide gel. Background technique [0002] Due to the advantages of low density, high temperature resistance, corrosion resistance, high permeability, good oxidation resistance and thermal shock resistance, porous silicon carbide ceramics are widely used in high temperature gas filter materials, catalyst carriers, gas combustion chamber media and refractory materials. It has broad application prospects. At present, the porous ceramics that have been widely used are mostly oxide ceramics, but they have disadvantages such as poor high-temperature performance and insufficient corrosion resistance, and porous silicon carbide ceramics can just make up for these deficiencies; in addition, many special fields require porous ceramic materials. The performance of silicon carbide puts forward higher requirements,...

AI Technical Summary

Problems solved by technology

However, these traditional methods for preparing porous ceramics usually need to add a large amount of organic pore-forming agents and binders. When organic matter is cracked at high temperature, a large amount of volatiles will be generated, causing environmental pollution and other problems. In addition, these pore-forming agents are expensive and have a large loss, resulting in The preparation cost of porous silicon carbide ceramics is relatively high