Method for preparing silicon nitride/silicon carbide porous ceramic

Abstract

The present invention belongs to the field of porous ceramic material technology, and is the preparation process of one low cost and high performance porous silicon nitride / silicon carbide ceramic. The preparation process includes compounding material, forming and sintering as the conventional ceramic material preparing steps. It features that phenolic resin used as pore creating agent and carbon source is in-situ produced into SiC phase through the carbon hot reduction during sintering; and that Si3N4, Al2O3, Y2O3 and phenolic resin in certain proportion are produced into slurry through adding anhydrous alcohol and mixing for 12-24 hr and stoved into powder; and that the ceramic powder is processed through formation, cracking to eliminate glue, carbon hot reduction and sintering to produce the porous ceramic material with porosity of 40-70 %, strength of 70-160 MPa and low cost.

Description

technical field [0001] The invention belongs to the technical field of porous ceramics, and relates to a preparation method of low-cost and high-performance silicon nitride / silicon carbide porous ceramics. Background technique [0002] The rapid development of industry, the increase and agglomeration of population, and the expansion of urban scale have gradually exposed environmental pollution problems, which have become increasingly serious and have become serious obstacles to the sustainable development of human beings. At present, environmental protection is an urgent problem that human beings face. In many industrial sectors, how to deal with high temperature, high pressure and dusty gas is always an urgent issue. For high-temperature smoke and dust, the ideal method is to filter dust, the most critical of which is to choose filter materials. [0003] Porous ceramics is a kind of ceramic material with gas phase as the main phase. Compared with other porous materials, it...

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Problems solved by technology

Wherein the pore-forming agent method is an important process for preparing porous ceramics, which can prepare products with complex shapes, such as Lyckfeldt et al. ) used starch as a pore-forming agent to prepare Al2O3 porous ceramics, Chinese patent 03116370.X used yeast powder as a pore-forming agent to prepare silicon carbide porous ceramics, and Chinese patent 03132960.8 used amide salts as a pore-forming agent to prepare porous ceramics, but this Porous ceramics prepared by this method have low strength

Tatsuki et al. (Jian-feng Yang, Guo-Jun Zhang, Nanoki Kondo, Tatsuki Ohji, Acta Materialia50, 2002, 4831-4840, Japanese Patent Laid-Open 2002-201083) prepare Si with nano carbon powder 3 N 4 Porous ceramics, Si after sintering 3 N 4 The porosity of porous ceramics is 50-60%, and the linear shrinkage rate is 2-3%. Although porous ceramics with a strength greater than 100Mpa can be prepared, the cost of using nano-carbon powder as a carbothermal reducing agent is too high

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