A kind of silicon nitride bonded silicon carbide ceramic filter and preparation method thereof

Abstract

The invention discloses a silicon nitride bonded silicon carbide ceramic filter and a preparation method thereof. The ceramic filter is prepared from silicon carbide sand, kaolin, metal silicon powder, additives and binders in a certain ratio. The preparation method is as follows: 1. Ball mill kaolin, metal silicon powder and additives to obtain a small material; 2. Add the binder to silicon carbide, mix evenly, add the small material, and mix well to obtain a mixed material; 3. Mix the mixture 4. Add the granules to the mold and press to form a porous wet billet; 5. Dry the wet billet to obtain a dry billet; 6. Put the dry billet in nitriding Sintering in a furnace to obtain a primary sintered product; 7. Immerse the primary sintered product in the metal silicon powder suspension, take it out and continue sintering. The ceramic filter has high granule binding strength, no slag drop, high temperature resistance, good thermal shock resistance and thermal stability, high filtration precision, high porosity, and concentrated pore diameter distribution. The method is simple, convenient to operate and 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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