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Quick crystallization method for realizing amorphous silicon nitride powder by taking silica powder as additive

A technology of silicon nitride powder and crystalline silicon nitride powder, which is applied in the field of preparation of ultrafine silicon nitride powder, can solve the problems of high cost and long process time of amorphous silicon nitride crystallization process, and achieve the promotion of phase transition Process, mass production of product purity, effect of shortening crystallization time

Active Publication Date: 2011-05-18
UNIV OF SCI & TECH BEIJING
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0006] The purpose of the present invention is to use the promoting effect of silicon powder in the crystallization process of amorphous silicon nitride to solve the problems of long time and high cost in the crystallization process of amorphous silicon nitride, and realize the use of amorphous silicon nitride in batches Method for large-scale production of α-phase silicon nitride powder by crystallization

Method used

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  • Quick crystallization method for realizing amorphous silicon nitride powder by taking silica powder as additive
  • Quick crystallization method for realizing amorphous silicon nitride powder by taking silica powder as additive
  • Quick crystallization method for realizing amorphous silicon nitride powder by taking silica powder as additive

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Effect test

Embodiment 1

[0036] Amorphous silicon nitride powder with an average particle size of 0.2 μm and silicon powder with 10 μm are placed in a sieving device for sieving to remove large particles formed due to agglomeration and other reasons. Then, the two powders were put into the powder mixing device according to the mass ratio of silicon nitride powder: silicon powder=95:5 to fully mix, and then the mixed raw materials were put into a vacuum drying box and dried at 90°C for 8 hours. Put the dried raw material into the sieving device again for sieving, further remove the large-size agglomerated powder, and then put it into the crystallization heat treatment device, after ventilation, heat treatment in a nitrogen atmosphere at 1450°C for 30 minutes, and cool it out of the furnace to obtain super Fine silicon nitride powder. According to X-ray diffraction analysis, the content of α-phase silicon nitride in the product is more than 80%, the content of uncrystallized amorphous silicon nitride is ...

Embodiment 2

[0038] Amorphous silicon nitride powder with an average particle size of 0.2 μm and silicon powder with 10 μm are placed in a sieving device for sieving to remove large particles formed due to agglomeration and other reasons. Then, the two powders were put into the powder mixing device according to the mass ratio of silicon nitride powder: silicon powder=70:30 to fully mix, and then the mixed raw materials were put into a vacuum drying box and dried at 90°C for 8 hours. Put the dried raw material into the sieving device again for sieving, further remove the large-size agglomerated powder, and then put it into the crystallization heat treatment device, after ventilation, heat treatment at 1450℃ in a nitrogen atmosphere for 20 minutes, and cool it out of the furnace to obtain a super Fine silicon nitride powder. According to X-ray diffraction analysis, the content of α-phase silicon nitride in the product is more than 90%, the content of uncrystallized amorphous silicon nitride i...

Embodiment 3

[0040] Amorphous silicon nitride powder with an average particle size of 0.2 μm and silicon powder with 10 μm are placed in a sieving device for sieving to remove large particles formed due to agglomeration and other reasons. Then put the two powders into the powder mixing device according to the mass ratio of silicon nitride powder: silicon powder=50:50 to fully mix, then put the mixed raw materials into a vacuum drying oven and dry them at 90°C for 8 hours. The dried raw materials are put into the sieving device again for sieving to further remove the large-size agglomerated powder, and then put into the crystallization heat treatment device, after ventilation, heat treatment in a nitrogen atmosphere at 1500°C for 15 minutes, and cool down after being discharged from the furnace to obtain super Fine silicon nitride powder. According to X-ray diffraction analysis, the α-phase silicon nitride content of the product is more than 75%, the β-phase silicon nitride content is less t...

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Abstract

The invention discloses a quick crystallization method for realizing amorphous silicon nitride powder by taking silica powder as additive, belonging to the technical field of preparation of ultrafine silicon nitride powder. The quick crystallization method is characterized in that the amorphous silicon nitride powder and silicon powder serving as the additive are fully mixed at the weight ratio of (98-50):(2-50); then the mixture is put into a high-temperature nitrogen furnace after being screened and dried for crystallizing the amorphous silicon nitride powder; the silicon powder is added to be subjected to combustion synthesis reaction together with nitrogen to generate alpha-phase silicon nitride while the crystallization time for the amorphous silicon nitride is effectively shortened; the final product is the alpha-phase silicon nitride powder, and the content of the silicon in the product is below 0.1%. The silicon powder serving as the crystallization can effectively accelerate the crystallization process of the amorphous silicon nitride powder, thus the nitriding of the nitrogen powder is completed while the crystallization time is greatly shortened. The method has the advantages of high production efficiency, simple equipment, quick energy conservation and high product purity, is convenient to operate, and is especially suitable for producing the high-quality silicon nitride powder with high alpha-phase content on batch by utilizing the amorphous silicon nitride powder.

Description

Technical field [0001] The invention belongs to the technical field of preparation of ultrafine silicon nitride powder, and relates to a method for rapidly crystallization of amorphous silicon nitride powder using silicon powder as an additive, which can produce high-purity and high-alpha phases in batches under high temperature and normal pressure. Silicon nitride ultrafine powder. Background technique [0002] Among various ceramic materials, silicon nitride (Si 3 N 4 ) Ceramics is a new type of engineering material with the most development potential and application market. Because of its high specific strength, high specific mode, high temperature resistance, oxidation resistance and wear resistance, and high thermal shock resistance, silicon nitride ceramics have special applications in the working environment of high temperature, high speed, and strong corrosive media. value. [0003] High quality Si 3 N 4 The preparation of ceramic products requires high-quality Si 3 N 4 P...

Claims

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Application Information

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IPC IPC(8): C04B35/626C04B35/584
Inventor 李延辉王立尹少武杨福明
Owner UNIV OF SCI & TECH BEIJING
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