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Preparation method for narrow size distribution high-purity silicon nitride powder

A narrow particle size distribution, silicon nitride powder technology, applied in chemical instruments and methods, nitrogen compounds, inorganic chemistry, etc., can solve the problems of wide particle size distribution, high metal impurity content, affecting the use effect, etc., to ensure product purity. Effect

Inactive Publication Date: 2016-12-14
HEBEI COREFRA SILICON NITRIDE MATERIAL
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  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0003] From the domestic index test, the particle size of silicon nitride powder is mainly concentrated between 0.5um~5um, the particle size distribution is wide, and the content of metal impurities is high, which greatly affects the later use effect

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0016] (1) Add silicon nitride diluent to 10~30um high-purity silicon powder. The amount of silicon nitride diluent added is 10% of the high-purity silicon powder. No additives are used, and the raw materials for nitriding reaction are obtained by mixing evenly;

[0017] (2) Lay the nitriding reaction raw materials in step (1) into a layer of granular materials with multi-stage granularity and precise proportioning, and place them in the sintering furnace, and feed nitrogen to replace the air in the furnace. The nitrogen purity is 99.99%, and continue to feed Nitrogen, heated to 1400 ° C, nitriding reaction 5h, high-purity silicon powder and nitrogen fully react to obtain silicon nitride;

[0018] (3) After cooling to room temperature, the silicon nitride obtained in step (2) is crushed and subdivided by airflow milling to obtain high-purity silicon nitride powder with a narrow particle size distribution. The purity of the high-purity silicon nitride powder is 99.99%, particle...

Embodiment 2

[0020] (1) Add silicon nitride diluent to 20~50um high-purity silicon powder, the amount of silicon nitride diluent added is 20% of the high-purity silicon powder, no additives are used, and the nitriding reaction raw materials are obtained by mixing evenly;

[0021] (2) Lay the nitriding reaction raw materials in step (1) into a layer of granular materials with multi-stage granularity and precise proportioning, and place them in the sintering furnace, and feed nitrogen to replace the air in the furnace. The nitrogen purity is 99.99%, and continue to feed Nitrogen, heated to 1420 ° C, nitriding reaction 20h, high-purity silicon powder and nitrogen fully react to obtain silicon nitride;

[0022] (3) After cooling to room temperature, the silicon nitride obtained in step (2) is crushed and subdivided by airflow milling to obtain high-purity silicon nitride powder with a narrow particle size distribution. The purity of the high-purity silicon nitride powder is 99.999%, particle s...

Embodiment 3

[0024] (1) Add silicon nitride diluent to 10~40um high-purity silicon powder. The amount of silicon nitride diluent added is 12% of the high-purity silicon powder. No additives are used, and the raw materials for nitriding reaction are obtained by mixing evenly;

[0025] (2) Lay the nitriding reaction raw materials in step (1) into a layer of granular materials with multi-level granularity and precise proportioning, and place them in the sintering furnace, and pass in nitrogen to replace the air in the furnace. The purity of nitrogen is 99.999%, and continue to pass in Nitrogen, heated to 1450 ° C, nitriding reaction 10h, high-purity silicon powder and nitrogen fully react to obtain silicon nitride;

[0026] (3) After cooling to room temperature, the silicon nitride obtained in step (2) is crushed and subdivided by airflow milling to obtain high-purity silicon nitride powder with a narrow particle size distribution. The purity of the high-purity silicon nitride powder is 99.99...

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Abstract

The invention relates to a preparation method for narrow size distribution high-purity silicon nitride powder and belongs to the technical field of preparation of silicon nitride powder. The preparation method specifically comprises the steps that firstly, silicon nitride diluent is added into high-purity silicon powder and mixed to be uniform, and a nitridation reaction raw material is obtained; then, nitridation reaction conditions are controlled, silicon nitride is obtained; finally, silicon nitride obtained after the reaction is ground to be fine through an airflow mill and graded, and the narrow size distribution high-purity silicon nitride powder is obtained. According to the process, no additive is used, the heat energy released through the reaction can be fully utilized by multi-level size precisely-matched grain layers, the purity of the product is guaranteed through multiple levels of purification, and the process is economical, efficient, environmentally friendly and suitable for large-scale production.

Description

technical field [0001] The invention relates to a method for preparing high-purity silicon nitride powder with narrow particle size distribution, and belongs to the technical field of silicon nitride powder preparation. Background technique [0002] Silicon nitride has the characteristics of high hardness, wear resistance, high temperature resistance, small thermal expansion coefficient, strong corrosion resistance, and resistance to cold and heat shocks. It has a wide range of applications, among which high-purity silicon nitride is mainly used in high-performance ceramic parts and photovoltaic industry. High-performance silicon nitride ceramics have excellent mechanical properties, thermal properties and chemical stability, and can withstand harsh working environments that metal or polymer materials cannot withstand. The key to making high-performance ceramics lies in the high purity of silicon nitride powder and narrow particle size distribution; polysilicon ingot castin...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C04B35/626C04B35/584C01B21/068
Inventor 张嵘刘久明
Owner HEBEI COREFRA SILICON NITRIDE MATERIAL