A method for preparing porous ceramics by low-temperature sintering

Abstract

The invention discloses a method of preparing porous ceramic through low-temperature sintering. In the invention, a method of coating ceramic particles with silicon sol is employed to achieve surface modification of the particles, so that a ceramic powder, which is difficult to sinter, can be subjected to surface fusion at a low temperature, thereby promoting sintering mass transmission among the particles and forming a high-strength neck part. A typical preparation method includes the steps of: 1) dissolving a gel-casting reagent, comprising an organic monomer, MBAM, (NH4)2S2O4 and TEMED in the silicon sol having certain concentration to prepare a pre-mixed liquid; 2) adding raw material particles to the pre-mixed liquid, and controlling the pH to coat the particles; 3) performing stacked pore forming to the particles, and performing polymerization and curing through a reaction at a certain temperature to form a green body; and 4) drying and low-temperature-sintering the green body to form the porous ceramic. The low-temperature ceramic sintering technology not only is free of damage on pore structures but also is simple in process. The porous ceramic can be used in the field of high temperature separation.

Description

technical field [0001] The invention belongs to the technical field of porous ceramics, and relates to a method for preparing porous ceramics by low-temperature sintering. Background technique [0002] In today's era, porous ceramic materials have penetrated into many fields. Many scientific fields such as environmental protection, energy saving, chemical industry, petroleum, smelting, food, pharmaceuticals, and biomedicine are inseparable from porous ceramic materials, especially in filtration, sound absorption, electrode materials, It plays an irreplaceable role in catalysis, heat insulation, and biological materials. [0003] For high temperature resistant porous ceramics, materials such as Al 2 o 3 , SiC, Si 3 N 4 , AlN, etc., are widely used in aviation, aerospace and other fields. However, the firing temperature of these ceramics is very high (>1600°C), which undoubtedly puts forward higher requirements for sintering equipment and preparation conditions, and als...

AI Technical Summary

Problems solved by technology

In 1997, Journal of the European Ceramic Society impurity described in volume 17, pages 1459-1465, the method of coating alumina particles with boehmite sol to reduce the firing temperature of ceramics. This method avoids the clogging of pores, but alumina The microcrystalline alumina particles generated by the pyrolysis of the sol are difficult to sinter and compact at the sintering neck of the raw material particles, forming a loose porous structure, and the strength of the ceramic is insufficient; moreover, the alumina sol particles bring a large specific surface area to the porous ceramic, increasing the The friction resistance in the fluid flow is reduced, and the permeability of the pores is reduced; in addition, the pre-coating treatment of the particles makes the preparation process cumbersome, which is not conducive to industrialization

[0005] In short, there are many ways to reduce the sintering temperature of porous ceramics, but it is difficult to meet the requirements of simplicity without affecting the pore structure characteristics.

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