Silicon carbide whisker in-situ composite corundum high-temperature ceramic material and preparation method thereof

Abstract

The invention discloses a silicon carbide whisker in-situ composite corundum high-temperature ceramic material and a preparation method thereof, and belongs to the technical field of high-temperature ceramic materials. The silicon carbide whisker in-situ composite corundum high-temperature ceramic material is prepared from a composite raw material and a binder, wherein the composite raw material is prepared from the following raw materials in percentages by weight: 82-91.5% of alundum powder, 7-15% of carbonized rice husk powder, 0.5-2% of a catalyst and 0.2-1% of silica micro-powder or silicon powder; and the mass of the binder is 3-5% of total mass of the composite raw material. The used raw materials are low in price and wide in source; the preparation technology is simple; and the prepared product has the advantages of being good thermal shock resistance, high in high-temperature strength and good in volume stability and is suitable for popularization and application.

Description

technical field [0001] The invention relates to a silicon carbide whisker in-situ composite corundum high-temperature ceramic material, which belongs to the technical field of high-temperature ceramic materials. Background technique [0002] Corundum material has excellent properties such as high temperature resistance, high strength, high hardness, wear resistance, and strong corrosion resistance. widely used. But its fracture toughness is only 3~4MPa·m 1 / 2 , poor thermal shock resistance, easy to crack under severe thermal shock, which limits its excellent performance and wider application in high temperature environments. In recent decades, researchers at home and abroad have improved the fracture toughness by adding zirconia to corundum materials or introducing silicon carbide whiskers. The former is improved through the martensitic transformation of zirconia and microcrack toughening. The latter is improved by adding pre-synthesized or in-situ-generated silicon carbi...

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Problems solved by technology

Although the two can improve the toughness of corundum materials to a certain extent, because the martensitic transformation has a strong dependence on temperature (1170°C and 950°C when heating up and cooling down), the resistance to corundum will be weakened or lost at high temperatures. The toughening effect of the material; the pre-synthesized silicon carbide whiskers are mostly agglomerated, and it is difficult to disperse evenly in the corundum matrix during the mixing process, and cannot fully exert its toughening effect, and it is located between the corundum particles, making the diffusion of corundum The extended mass path is not conducive to sintering and densification; the silicon carbide whisker in-situ composite corundum materials currently studied mostly use multi-graded alumina particles as the main material, and high-purity Si powder, SiO 2 Micro-nano powder is the silicon source, carbon black, graphite or phenolic resin is the carbon source, and it is obtained by firing under argon, nitrogen, hydrogen or vacuum conditions. The growth and development of whiskers provides enough space, and the long-diameter ratio of the obtained silicon carbide whiskers is small, which makes a limited contribution to the toughness of the matrix material, and the raw materials used are expensive, the process is complicated, and the preparation process is difficult to control. These all limit the production of corundum products. Promotion and application in industry

[0003] In the existing research, the invention patent with the patent application publication number CN101880173A discloses a silicon carbide whisker in-situ toughened alumina ceramic, and the invention patent with the patent application publication number CN101880163A discloses a silicon carbide whisker original The manufacturing method of position toughened alumina ceramics, both of these two patents use the four-component additive MO (M is one of Mg, Ba, Be, Ca)-SiO 2 –C–L x o y (L is a transition metal element, one of Fe, Ni, Cu) added to alumina powder, with phenolic resin or polyvinyl alcohol as a binder, and pressed by a mixer to make a green body, which was placed at 250 Heat treatment at ℃ for 20 minutes to remove the binder, then place in a vacuum furnace to evacuate to 4-5Pa, and then fill with nitrogen for protection. After firing at 1300-1400 ℃, silicon carbide whisker in-situ composite alumina ceramics are obtained. The method is as follows Defects: 1. The cost of raw materials is high; 2. The firing process is complicated and the process is difficult to control; 3. The mechanical properties and microstructure of the prepared materials are not explained, so that the popularization and application are limited

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