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Method for preparing silicon nitride powder with high alpha phase content at low temperature

A technology of phase silicon nitride powder and silicon powder, which is applied in the field of low-temperature preparation of high-α-phase silicon nitride powder, which can solve the problems of low volume diffusion and grain boundary diffusion speed, difficulty in achieving sintering densification, and small sintering driving force. , to achieve the effects of easy control, high cost, and short nitriding cycle

Inactive Publication Date: 2018-02-06
HEBEI COREFRA SILICON NITRIDE MATERIAL
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

But Si 3 N 4 It is a strong covalent bond compound, its diffusion coefficient is low, the volume diffusion and grain boundary diffusion rate causing densification are small, and the sintering driving force is small, so it is difficult to achieve sintering densification

Method used

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  • Method for preparing silicon nitride powder with high alpha phase content at low temperature
  • Method for preparing silicon nitride powder with high alpha phase content at low temperature

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Embodiment 1

[0023] A method for preparing a high α-phase silicon nitride powder, the preparation method comprising the following steps:

[0024] Step 1, the raw material particle size 3 μm silicon powder, particle size 20nm silicon powder, 2 μm α-phase silicon nitride and catalyst mixture ball mill activation;

[0025] Step 2. The ball-milled mixture obtained in Step 1 is kept at 1250° C. for 12 hours in a mixed atmosphere of nitrogen and argon to obtain silicon nitride.

Embodiment 2

[0027] A method for preparing a high α-phase silicon nitride powder, the preparation method comprising the following steps:

[0028] Step 1, the raw material particle size 25 μm silicon powder, particle size 50nm silicon powder, 3 μm α-phase silicon nitride and catalyst mixture ball mill activation;

[0029] Step 2. The ball-milled mixture obtained in Step 1 is kept at 1300° C. for 10 h in a mixed atmosphere of nitrogen and argon to obtain silicon nitride.

Embodiment 3

[0031] A method for preparing a high α-phase silicon nitride powder, the preparation method comprising the following steps:

[0032] Step 1, the raw material particle size 48 μm silicon powder, particle size 85nm silicon powder, 8 μm α-phase silicon nitride and catalyst mixture ball mill activation;

[0033] Step 2. The ball-milled mixture obtained in Step 1 is kept at 1200° C. for 20 h in a mixed atmosphere of nitrogen and argon to obtain silicon nitride.

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Abstract

The invention provides a method for preparing silicon nitride powder with high alpha phase content at a low temperature and belongs to the technical field of powder preparation. The method comprises the following steps: (1) performing ball milling and activation on a mixture of silicon powder as a raw material, nanometer silicon powder, a diluent and a catalyst; (2) performing heat preservation onthe ball milled mixture obtained in the step (1) under a mixed atmosphere of nitrogen and argon at 1200-1300 DEG C for 2-24 h to obtain silicon nitride with alpha content higher than 95%, and performing ball milling and grinding on silicon nitride to obtain the silicon nitride powder. According to the method for preparing the silicon nitride powder with high alpha phase content at the low temperature, the silicon nitride powder with the high alpha phase content is prepared efficiently. The preparation method has the advantages that production is simple, the technology is controllable, preparation temperature is reduced, energy is saved, and the method is suitable for large-scale industrial production of factories.

Description

technical field [0001] The invention belongs to the technical field of inorganic chemistry. Specifically, it relates to a method for preparing high α-phase silicon nitride powder at low temperature. Background technique [0002] Si 3 N 4 It is an important structural ceramic material with unique excellent properties such as high strength, high hardness, wear resistance, corrosion resistance and high thermal conductivity. It has a wide range of applications in national defense, energy, aerospace, machinery, petrochemical, metallurgy, electronics and other fields Applications. But Si 3 N 4 It is a strong covalent bond compound, its diffusion coefficient is low, the volume diffusion and grain boundary diffusion rate causing densification are small, and the sintering driving force is small, so it is difficult to achieve sintering densification. Silicon nitride has two crystal forms, among which α-Si 3 N 4 Belongs to low temperature stable crystal form, β-Si 3 N 4 It is...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C01B21/068
CPCC01B21/0682C01P2002/72
Inventor 吴诚刘久明
Owner HEBEI COREFRA SILICON NITRIDE MATERIAL