Method for preparing silicon carbide porous ceramic using gelatin wrapping-freeze drying process

Abstract

The invention discloses a preparing method of carborundum porous ceramic through gel parcel-freezing drying technique, which comprises the following steps: preparing alumina sol; using alumina sol to parcel the carborundum particle; controlling the solid sol content; freezing sol slurry; drying; moulding; sintering; possessing oriental and mutual connecting pore with hole opening rate at 40-90% and aperture at 1-500 um; connecting carborundum through mullite; dispersing aluminium isopropoxide and carborundum particle in the isopropanol; hydrolyzing aluminium isopropoxide to form alumina sol slurry; adding adhesive and defoamer; casting; moulding; removing air to form vacuum; freezing to dry; forming porous blank; detackifying; sintering in the air; oxidizing carborundum particle surface into silica and alumina to obtain mullite; combining carborundum particle to obtain the porous carborundum ceramics.

Description

technical field [0001] The invention relates to a method for preparing silicon carbide porous ceramics by gel encapsulation-freeze drying process, more precisely, a method for preparing silicon carbide porous ceramics with directional pore structure and high porosity by using gel encapsulation-freeze drying process , belongs to the field of porous ceramics. Background technique [0002] Automobile exhaust, industrial smoke and chemical waste gas have brought serious pollution to the environment, and there is an urgent need to develop high temperature resistant, thermal shock resistant, high permeability filter and catalyst carrier materials. In addition to good high-temperature performance and permeability, silicon carbide porous ceramics also have low thermal expansion coefficient, high thermal conductivity and excellent mechanical properties, so they are one of the most ideal candidate materials for filters and catalyst supports. [0003] Foam impregnation method is a com...

AI Technical Summary

Problems solved by technology

However, it is difficult to obtain silicon carbide porous ceramics with a porosity greater than 80%, a pore diameter of 0.1-100 μm, and an oriented pore structure by the above-mentioned methods.

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