High-roundness high-purity silicon carbide ultrafine powder material

Abstract

The invention discloses a high-roundness high-purity silicon carbide ultrafine powder material. Through two times of smashing shaping of gas flow medium smashing shaping and grinding shaping with analysis and purification, high-purity 6H-SiC micro powder synthesized in situ is processed into the ultrafine powder material with the roundness of 0.950 or above and the D50 value of 1.6-2.0 micrometers, so that the requirements on sintering precise ceramic products are met, the precise ceramic products (such as a silicon carbide ceramic sealing shaft sleeve, a silicon carbide ceramic roller and a silicon carbide ceramic nozzle) sintered from the ultrafine powder material overcome the sintering defects of low finished product rate, inconsistent compactness and the like which are high in possibility in conventional sintering, and the sintered silicon carbide ceramic is good in quality consistency, has heat shock resistance and high temperature resistance when in use, and can avoid the disadvantage of different service lives and the like. Through testing, the volume density of a finished part sintered by adopting the prepared silicon carbide ultrafine powder is greater than or equal to 3.04 g / cm<3>, the porosity rate is less than 0.3%, the highest use temperature is 1380 DEG C, and the use requirements of the precise silicon carbide products can be completely met.

Description

technical field [0001] The invention relates to a raw material for sintering silicon carbide precision ceramic products, in particular to a high-circularity and high-purity silicon carbide ultrafine powder material used for sintering silicon carbide precision ceramic products. Background technique [0002] Due to its low density, high temperature strength, strong oxidation resistance, good wear resistance, good thermal stability, small thermal expansion coefficient, high thermal conductivity, high hardness, thermal shock resistance and chemical corrosion resistance, silicon carbide ceramic materials are excellent. It has been widely used in the fields of automobile industry, mechanical chemical industry, environmental protection, space technology, high-tech information industry and so on. For example, silicon carbide is used in various corrosion-resistant containers and pipes in petrochemical industry, various wear-resistant and high-temperature-resistant parts in the machin...

AI Technical Summary

Problems solved by technology

[0004] The invention patent "Special Ceramic Material for Sintering Silicon Carbide Ceramic Membrane" (Patent No. 201410002513.6) applied by our company on January 4, 2014, has been able to process the silicon carbide ceramic material into a circularity greater than 0.95, and a D50 value of There are two kinds of micropowder materials of 170-190 microns and 190-230 microns. These two kinds of granular materials are better in sintering silicon carbide ceramic membranes, which can fully meet the design requirements and use requirements. However, if they are used for sintering carbonization Silicon precision ceramic products, such as shaft sleeves for shaft protection in high-speed rotation of wear-resistant and corrosion-resistant pumps, and ceramic valve cores for check valves, etc., due to the large particle size of silicon carbide fine powder, the sintered products are due to tolerances. Coordination, surface roughness and other factors cannot meet the quality requirements of the required products

[0005] In order to ensure the sintering quality of silicon carbide precision ceramic products, it is necessary to process ultrafine silicon carbide powder with a circularity of 0.950, a median value of less than 5 microns and finer. However, due to the limitation of the current processing technology, ultrafine silicon carbide powder The processing has become a technical problem in the industry