A method for preparing submicron high-alpha-phase silicon nitride powder by combustion synthesis without additives

A phase silicon nitride powder, sub-micron technology, applied in the field of preparation of high α phase silicon nitride ceramic powder, can solve complex grinding process and other problems, achieve simple equipment, improve reaction activity, and save energy

Active Publication Date: 2015-11-25
天津纳德科技有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

However, ammonium bicarbonate, urea, etc. will also produce part of NH during the reaction process. 3 , CO, HCN and other toxic substances, and the final product particles are not sub-micron, so a more complicated subsequent grinding process is required to obtain ultra-fine silicon nitride powder

Method used

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  • A method for preparing submicron high-alpha-phase silicon nitride powder by combustion synthesis without additives
  • A method for preparing submicron high-alpha-phase silicon nitride powder by combustion synthesis without additives
  • A method for preparing submicron high-alpha-phase silicon nitride powder by combustion synthesis without additives

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0038] Mix 400-mesh silicon powder (purity>99wt%) with alcohol, use silicon nitride balls as the medium, and mill on a planetary ball mill for 36 hours. After the slurry is vacuum filtered, it is pickled with a mixed solution of hydrofluoric acid and hydrochloric acid. , vacuum-dried at 60°C after suction filtration. Finally, ultrafine silicon powder raw materials with an average particle size of 0.58 μm are obtained. Weigh raw materials according to weight ratio, ultrafine silicon powder is 33%, silicon nitride (α phase content is 91wt%, average particle size 2μm) is 67%, after mixing with alcohol, using silicon nitride ball as medium, rolling Ball milled on a ball mill for 12 h, followed by vacuum drying at 60 °C. After passing through a 200-mesh sieve, it is loosely packed in a porous graphite boat and placed in a combustion synthesis device. After vacuuming, fill it with 3MPa high-purity nitrogen. Use titanium powder as the ignition agent to induce combustion synthesis ...

Embodiment 2

[0040] Mix 300-mesh silicon powder (purity>99.5%) with alcohol, use silicon nitride balls as the medium, and mill on a planetary ball mill for 24 hours. After the slurry is vacuum-filtered, it is pickled with hydrofluoric acid solution. Dry under vacuum at 70°C. Finally, ultrafine silicon powder raw materials with an average particle size of 0.74 μm are obtained. Weigh raw materials according to weight ratio, ultrafine silicon powder is 40%, silicon nitride (α phase content is 92wt%, average particle size 2.6μm) is 60%, after mixing with alcohol, using silicon nitride ball as medium, in Ball milled on a planetary ball mill for 12 h, followed by vacuum drying at 70 °C. After passing through a 100-mesh sieve, it is loosely packed in a porous graphite boat and placed in a combustion synthesis device. After vacuuming, fill it with 4MPa high-purity nitrogen. Use titanium powder as the ignition agent to induce combustion synthesis reaction. After the combustion reaction is over,...

Embodiment 3

[0042] Mix 400-mesh silicon powder (purity >99%) with alcohol, use agate balls as the medium, and mill on a planetary ball mill for 28 hours. After the slurry is vacuum filtered, it is pickled with a mixed solution of hydrofluoric acid and sulfuric acid. After filtration, it was dried under vacuum at 60°C. Finally, ultrafine silicon powder raw materials with an average particle size of 0.61 μm are obtained. Weigh raw materials according to weight ratio, ultrafine silicon powder is 36%, silicon nitride (α phase content is 91wt%, average particle size 2μm) is 64%, after mixing with alcohol, using agate balls as the medium, on a rolling ball mill Ball milled for 16 h, followed by vacuum drying at 60 °C. After passing through a 100-mesh sieve, it is loosely packed in a porous graphite boat and placed in a combustion synthesis device. After vacuuming, fill it with 4.5MPa high-purity nitrogen. Use titanium powder as the ignition agent to induce combustion synthesis reaction. Aft...

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Abstract

The invention discloses a process for preparing a submicron-order high-alpha-phase superfine silicon nitride powder body by virtue of a combustion synthesis method without using any additive by using high-activity superfine silicon powder as a raw material, and particularly relates to an industrial technology for continuous production by using the process, and belongs to the field of inorganic nonmetal powder materials. The process comprises the following specific steps: performing co-processing of ball-grinding and pickling on a silicon powder raw material to obtain superfine silicon powder with high combustion activity; then adding the silicon powder and a silicon nitride diluting agent in proportion, ball-grinding to ensure that the silicon powder and the silicon nitride diluting agent are uniformly mixed without using the additive, distributing materials in a combustion synthesis reaction device after drying, and inducing a reaction at a lower pressure to obtain the submicron-order superfine silicon nitride powder body with an alpha phase of 85-95wt%. The process is free from of pollution and toxins due to no use of any additive; the prepared product is high in content of the alpha phase, superfine in particle size, high in sintering activity, and free from complicated posttreatment process.

Description

technical field [0001] The invention relates to the preparation technology of high-alpha-phase silicon nitride ceramic powder, in particular to a process technology for preparing submicron-level high-alpha-phase silicon nitride powder by combustion synthesis under low pressure without additives, and belongs to the field of inorganic non-metallic powder materials . Background technique [0002] As an important high-temperature structural ceramic material, silicon nitride ceramics have many excellent properties such as low density, low expansion coefficient, high thermal conductivity, high hardness, good thermal and chemical stability, corrosion resistance, and wear resistance. , Widely used in ceramic engines, cutting tools, wear-resistant devices and other fields. The important position of high α-phase silicon nitride powder as its main raw material can be seen. In addition, silicon nitride powder also has important applications in the field of solar energy. Silicon nitri...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C01B21/068C04B35/584C04B35/626
Inventor 陈克新葛一瑶邹艺峰崔巍刘光华
Owner 天津纳德科技有限公司
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