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A low-temperature sintering method for ultra-high temperature ceramics

A technology of ultra-high-temperature ceramics and low-temperature sintering, which is applied in the field of dense ceramic preparation. It can solve the problems of low atomic self-diffusion coefficient, difficulty in preparing ultra-fine powder, and easy introduction of impurities such as oxygen, so as to reduce the sintering process and reduce the possibility , The effect of prolonging the burning time

Inactive Publication Date: 2020-06-09
CHINA ACADEMY OF SPACE TECHNOLOGY
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

At present, non-oxide sintering aids are mainly added in the form of crystal powder, both of which are non-oxides with high covalent bonds, and have low atomic self-diffusion coefficients. This type of sintering aids can only function above 1900°C to achieve densification. In order to improve the activity of sintering aids, ultrafine powders are often used. For non-oxide powders, the preparation of ultrafine powders is difficult, and it is easy to bring in impurities such as oxygen.

Method used

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  • A low-temperature sintering method for ultra-high temperature ceramics
  • A low-temperature sintering method for ultra-high temperature ceramics
  • A low-temperature sintering method for ultra-high temperature ceramics

Examples

Experimental program
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Effect test

Embodiment 1

[0025] (1) Add 20ml polyborosilazane to 60ml n-hexane solvent, then mix with sieved ZrB 2 The ceramic powder is mixed at a mass ratio of 1:4 (that is, the mass ratio of polyborosilazane to ceramic powder is 1:4) to obtain a mixed slurry, and then the mixed slurry is put into a ball mill for 35 minutes, and the ball milling speed is 80r / min;

[0026] (2) After step (1) is completed, take out the mixed slurry and place it in a petri dish, and use n-hexane solvent to remove the remaining ZrO 2 Rinse off the mixed slurry on the grinding ball, let it stand at room temperature for 1 hour, then take out the mixed powder and put it into a hot-pressed graphite mold. The inner wall of the graphite mold is coated with BN, and the mixed powder and the inner wall of the graphite mold are covered with graphite paper. In order to prevent the mixed powder from reacting with the inner wall of the graphite mold at high temperature, use a cold press to cold press the mixed powder at 40MPa for 1...

Embodiment 2

[0030] (1) Add polyborosilazane to n-hexane solvent, then mix it with sieved SiC ceramic powder at a mass ratio of 1:4, then put the mixed slurry into a ball mill, mill for 30 minutes, and control the milling speed at 100r / min;

[0031] (2) After step (1) is completed, take out the mixed slurry and place it in a petri dish, and use n-hexane solvent to remove the remaining ZrO 2 Rinse off the mixed slurry on the grinding ball, put it at room temperature for 1 hour, then take out the slightly humid mixed powder and put it into a hot-pressed graphite mold. The inner wall of the graphite mold is coated with BN, and the powder and the mold are sealed with graphite paper The inner wall is isolated to prevent the powder from reacting with the inner wall of the mold at high temperature, and the mixed slurry is cold-pressed at 40MPa for 10 minutes with a cold press;

[0032](3) After step (2) is completed, the graphite mold is put into a hot-press sintering furnace, and the furnace te...

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Abstract

The invention relates to a low-temperature sintering method of ultra-high-temperature ceramic, belonging to the technical field of preparation of compact ceramics. The ultra-high-temperature ceramic is a material capable of maintaining chemical stability in a high temperature environment (with a temperature higher than 2000 DEG C) and mainly contains certain high-melting-point transition metal compounds such as boride and carbide, and low-temperature sintering is carried out at 1650-1750 DEG C. The ultra-high-temperature ceramic prepared by virtue of the method is high in density.

Description

technical field [0001] The invention relates to a low-temperature sintering method for ultra-high-temperature ceramics, which belongs to the technical field of dense ceramic preparation. The ultra-high-temperature ceramics refer to a material that can maintain chemical stability in a high-temperature environment (above 2000 ° C), mainly including borides , some high-melting transition metal compounds including carbides, the low-temperature sintering refers to sintering at a temperature of 1650-1750°C. Background technique [0002] Due to their excellent properties in high temperature resistance, mechanics, tribology, electricity, heat transfer, etc., Ultra-high Temperature Ceramics (UHTCs) have attracted extensive attention both as high-temperature structural materials and functional materials. The essential difference from traditional oxide ceramics is that ultra-high temperature ceramics (non-oxide ceramics) have strong covalent bonds. This characteristic makes it have the...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C04B35/565C04B35/58C04B35/645
CPCC04B35/575C04B35/58078C04B35/645C04B2235/3856C04B2235/6562C04B2235/77
Inventor 李秉洋王鹏飞张雁曹莹泽王博
Owner CHINA ACADEMY OF SPACE TECHNOLOGY
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