Method for synthesizing silicon nitride powder by atmospheric pressure combustion

A technology of silicon nitride powder and combustion synthesis, which is applied in chemical instruments and methods, nitrogen compounds, inorganic chemistry, etc., can solve the problems of high equipment cost and poor safety, and achieve the goal of improving reactivity, increasing product output, and low cost Effect

Inactive Publication Date: 2005-08-24
TECHNICAL INST OF PHYSICS & CHEMISTRY - CHINESE ACAD OF SCI
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  • Abstract
  • Description
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  • Application Information

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Problems solved by technology

[0012] One of the objectives of the present invention is to provide a method for synthesizing silicon nitride powder by combustion under normal pressure in view of the disadvantages of high-pressure combustion synthesis requiring high-pressure special equipment, high equipment cost and poor safety.

Method used

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  • Method for synthesizing silicon nitride powder by atmospheric pressure combustion
  • Method for synthesizing silicon nitride powder by atmospheric pressure combustion
  • Method for synthesizing silicon nitride powder by atmospheric pressure combustion

Examples

Experimental program
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Embodiment 1

[0046] Si powder with an average particle size of 0.1 μm and Si powder with an average particle size of 0.5 μm 3 N 4 Powder, Si powder is 55% by weight, Si 3 N 4 24%, NH 4 After F 21% is mixed, put it into a planetary ball mill for 150 hours to make it fully mixed and activated, put the ball mill jar into a vacuum glove box, and after vacuuming, fill it with high-purity nitrogen until the nitrogen pressure reaches 0.11Mpa; Take out half of the mixed material in the vacuum glove box and place it in a porous graphite crucible so that the bulk density of the powder is 0.95-1.59g / cm 3 . Use a tungsten wire with a diameter of 0.5mm as the heating element, feed a current of 13 amperes, and ignite to induce the combustion of the raw material powder. After the combustion reaction lasts for 10 minutes, add the other half of the mixture to the upper part of the porous graphite crucible container, and wait for all the samples to react. After completion, the sample was cooled to roo...

Embodiment 2

[0048] 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, Si powder is 75% by weight, Si 3 N 4 After mixing 25%, put it into a ball mill tank that can be filled with protective gas, and fill it with NH 3 gas, and ball milled in a vibrating ball mill for 120 hours to make it fully mixed, and the amorphous phase content in the mixture was calculated by DSC / TG analysis to be 21wt%. Put the mixed material in a porous graphite crucible to keep the bulk density at 0.95-1.59g / cm 3 , put it into the air pressure sintering furnace; after vacuuming, fill it with high-purity nitrogen until the nitrogen pressure reaches 0.12Mpa; use a tungsten wire with a diameter of less than 0.5mm as the heating element, and feed a current of 16 amperes to ignite to induce the combustion of the raw material powder , after the combustion reaction lasts for 25 minutes, the air is released and the product is finely ground to obtain a si...

Embodiment 3

[0050] Si powder with an average particle size of 5 μm and Si powder with an average particle size of 30 nm 3 N 4 Powder, Si powder is 50% by weight, Si 3 N 4 12% mixed, put into an oven and dry at 100°C for 1.5 hours, take it out and add (NH 4 ) 2 CO 3 19%, NH 4 Cl 19%, then ultrasonically activated for 30 minutes, and then placed in a planetary ball mill for 120 hours of ball milling, filled with high-purity nitrogen protective gas in the ball mill tank to make it fully mixed and refined, and calculated by DSC / TG analysis. The crystal phase content was 30 wt%. Loosely install the mixed material in a porous ceramic cup to keep the bulk density at 0.95-1.59g / cm 3, put the porous ceramic cup into a modified civilian microwave oven; fill high-purity nitrogen gas from the bottom, and use flowing nitrogen gas as a protective gas; start the microwave source, and after heating for 1 minute, the raw material powder can be induced to burn, and the combustion reaction takes ab...

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Abstract

A process for synthesizing silicon nitride powder by atmospheric pressure combustion includes such steps as proportionally mixing Si powder with catalyst, adding silicon nitride for activating and combustion reaction. Its main product is Si3N4.

Description

technical field [0001] The invention belongs to the technical field of preparation of non-oxide superfine silicon nitride ceramic powder, and relates to a method for synthesizing silicon nitride powder by atmospheric pressure combustion, in particular to a method for synthesizing silicon nitride powder by atmospheric continuous combustion. Background technique [0002] Si 3 N 4 Ceramics are an important representative of non-oxide ceramic materials. Because of their excellent high strength, high hardness, wear resistance and chemical corrosion resistance, they are widely used in ceramic blades, bearings, wire drawing dies, rolls, etc. However, compared with metal-based materials, the high cost of silicon nitride ceramics restricts its large-scale application. Therefore, it is an international research hotspot to research and develop new low-cost preparation technology from the four links of milling-molding-sintering-processing. [0003] Internatio...

Claims

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Application Information

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