Silicon nitride combined silicon carbide ceramic filter and manufacturing method thereof

Abstract

The invention discloses a silicon nitride combined silicon carbide ceramic filter and a manufacturing method thereof. The ceramic filter is prepared from silicon carbide sand, kaolin, metal silicon powder, an additive and a binder in certain proportion. The manufacturing method comprises the following steps: 1, ball-milling kaolin, metal silicon powder and the additive to obtain small materials; 2, adding the binder into silicon carbide to uniformly mix, adding the small materials to uniformly mix to obtain a material mixture; 3, bundling the material mixture, uniformly mixing to obtain particles; 4, adding the particles into a mould to press and form, thereby obtaining porous wet blank; 5, drying the wet blank to obtain dry blank; 6, putting the dry blank into a nitriding furnace to sinter, thereby obtaining a primary sintered product; 7, soaking the primary sintered product into metal silicon powder suspension liquid, taking out and continuously sintering. The ceramic filter is highin particle bonding strength, does not have slag, is resistant to a high temperature, is good in thermal impact resistance and thermal stability, is high in filter precision, is high in aperture ratioand is intensive in gas hole diameter distribution. The method is simple, is convenient to operate, and is low in preparation cost.

Description

technical field [0001] The invention relates to the technical field of ceramic filtration, in particular to a silicon nitride bonded silicon carbide ceramic filter and a preparation method thereof. Background technique [0002] In the aluminum refining industry, the commonly used plate filter is a foam ceramic filter. The basic materials of the foam ceramic filter are alumina, zirconia, yttrium oxide, and silicon carbide. [0003] For alumina-based foam filters, the main problems are poor high temperature resistance, poor thermal shock resistance, poor thermal stability and low filtration accuracy. Taking the 30PPI (foam filter model) foam filter as an example, for 10μm or less The filtering capacity of the particles is only 30%, which is completely unable to meet the filtering requirements of precision aluminum products. [0004] For zirconia and yttrium oxide foam filters, the main problem is that they are expensive and harmful to the human body during processing. For ex...

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Problems solved by technology

Such as the Chinese patent "A Yttrium Oxide Foam Ceramic Filter" (201010511259.4), the ceramic filter has good high temperature resistance, high strength and good filtration performance, but its manufacturing process is complicated, and the price of yttrium oxide is high

[0005] At present, silicon carbide ceramic filters are more researched and developed, such as the Chinese patent "a silicon carbide ceramic filter plate" (201410704684.3), which has the advantage of adopting a three-layer structure, with a more reasonable pore gradient, adjustable pore It is not easy to block when it is used, and its disadvantage is that it does not emphasize its stability at high temperature, and the process is too complicated, and the preparation cost is relatively high

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