Temperature controlled combustion method for synthesizing powder of silicon nitride in alpha phase

A phase silicon nitride powder, combustion synthesis technology, applied in chemical instruments and methods, nitrogen compounds, inorganic chemistry, etc., can solve the problems of high silicon nitridation reaction pressure, complex induced reaction methods, long production cycle, etc. Withstanding pressure requirements, shortened production cycle, and less environmental pollution

Inactive Publication Date: 2006-07-19
TECHNICAL INST OF PHYSICS & CHEMISTRY - CHINESE ACAD OF SCI
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0010] One of the purposes of the present invention is to overcome the traditional synthetic Si 3 N 4 In the technology, there are shortcomings such as high pressure of silicon nitriding reaction, long production cycle, complicated induction reaction mode, large energy consumption and high cost. It provides a simple operation, short production cycle, and realizes temperature-controlled combustion to synthesize α-phase nitrogen at a lower pressure. The method of silicon powder

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0038] Si powder with an average particle size of 0.1 μm, Si with an average particle size of 0.5 μm 3 N 4 powder and (NH 4 ) 2 CO 3 , by weight, 60 parts of Si powder, Si 3 N 4 22 copies, (NH 4 ) 2 CO 3 18 parts, put them into the ball milling tank of the vibrating ball mill for 5 hours to make them fully mixed and activated; put the mixed material in a porous graphite crucible, place a spiral tungsten wire on the upper layer of the material, and tungsten wire The diameter is 0.5mm, and then put them together in the combustion synthesis reactor (the bulk density is about 0.8-2.0g / cm 3 ); After vacuuming, fill high-purity nitrogen gas from the bottom of the reactor until the nitrogen pressure reaches 4MPa; pass the spiral tungsten wire with a pulse current to make it generate heat, and induce the combustion of the raw material powder. After the combustion reaction lasts for 20 minutes, cool to room temperature, and then the residual N 2 Drain off and grind the prod...

Embodiment 2

[0040] Si powder with an average particle size of 5 μm, Si with an average particle size of 20 nm 3 N 4 Powder, (NH 4 ) 2 CO 3 and NH 4 Cl, by weight, 52 parts of Si powder, Si 3 N 4 28 copies, (NH 4 ) 2 CO 3 16 parts and NH 4 4 parts of Cl, sampled separately, first weighed Si powder and Si 3 N 4 After mixing, put it into an oven, dry at 100°C for 1.5 hours, take it out and add the weighed (NH 4 ) 2 CO 3 and NH 4 Cl, put them into the ball mill jar of the planetary ball mill for 3 hours and make them fully mixed; put the mixed materials in a porous graphite crucible, place a spiral tungsten wire on the upper layer of the materials, and put them together in the combustion synthesis reactor (The bulk density is about 0.8~2.0g / cm 3 ); After vacuuming, fill ammonia gas from the bottom to 0.1Mpa, and then fill high-purity nitrogen gas until the pressure in the reactor reaches 3Mpa; pass the spiral tungsten wire with a pulse current of 12A to make it generate heat...

Embodiment 3

[0042] Si powder with an average particle size of 0.5 μm and Si powder with an average particle size of 78 μm 3 N 4 Powder, by weight, 86 parts of Si powder, Si 3 N 4 6 parts, NH 4 2 parts of Cl, CO(NH 2 ) 2 3 parts, put into the ball mill tank of the planetary ball mill, ball mill for 4.5 hours, make it fully mixed, put the mixed material (a spiral tungsten wire is placed on the upper layer of the material) in a porous graphite crucible, and put it in the combustion synthesis reactor (The bulk density is about 0.8~2.0g / cm 3 ); After vacuuming, first fill ammonia gas to 0.5Mpa, then fill high-purity nitrogen gas until the pressure in the reactor reaches 2Mpa; pass the spiral tungsten wire with a pulse current of 12A to make it generate heat and induce the combustion of raw material powder , after the combustion reaction lasts for 40 minutes, vent the residual gas and finely grind the product to get the reaction product. The reaction product is analyzed by XRD with the ...

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Abstract

A process for preparing alpha-phase silicon nitride powder by temp-controlled combustion includes proportionally mixing silicon powder, silicon nitride diluent and catalyst, grinding, loading in reactor, filing N2 or the mixture of N2 and NH4 gas, and self-progressive combustion reaction.

Description

technical field [0001] The invention belongs to the field of inorganic non-metallic materials, and relates to a method for synthesizing α-phase silicon nitride powder by temperature-controlled combustion under relatively low pressure. Background technique [0002] Due to its excellent high-temperature mechanical properties and chemical stability, silicon nitride ceramics have received extensive attention and in-depth research all over the world, and are recognized as one of the typical advanced structural ceramics. With the wide application of silicon nitride ceramic materials in chemical industry, metallurgy, aviation and automobile industry, industrial departments and scientific and technological workers in various countries pay more and more attention to the research of silicon nitride. In recent years, the research on low-cost preparation of high-purity, ultra-fine silicon nitride powder is particularly active. [0003] In terms of phase composit...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C04B35/584C04B35/622C01B21/068
Inventor 杨筠林志明李江涛
Owner TECHNICAL INST OF PHYSICS & CHEMISTRY - CHINESE ACAD OF SCI
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