Method for rapidly combusting and synthesizing silicon nitride powder by using foaming agent capable of producing nitrogen while decomposing as additive

A silicon nitride powder, rapid combustion technology, applied in chemical instruments and methods, nitrogen compounds, inorganic chemistry, etc., can solve the problems of unstable process, high production cost, long production cycle, etc., to increase stability and production. Safety, the effect of increasing production safety and reducing production costs

Active Publication Date: 2012-06-06
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

The main problem is that the production cycle is as long as 72 hours, and the secondary nitriding is required and the energy consumption is large
Similarly, the carbothermal reduction process also has disadvantages such as long production cycle, complicated process, and high production cost; in addition, the content of impurities such as carbon and oxygen in the product is also high
The Japanese UBE company uses the silicon imine decomposition method to produce silicon nitride powder with a good degree of commercialization; the disadvantages of this method are: complex process, high production cost, easy corrosion problems in the production process, and chlorine high content
In summary: the traditional combustion synthesis process to prepare silicon nitride powder has the following defects: 1) low net yield; 2) high synthesis cost; 3) unstable process; 4) easy to introduce impurities into the product
This makes it still difficult to use the combustion synthesis process to prepare silicon nitride powder on a large scale

Method used

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  • Method for rapidly combusting and synthesizing silicon nitride powder by using foaming agent capable of producing nitrogen while decomposing as additive
  • Method for rapidly combusting and synthesizing silicon nitride powder by using foaming agent capable of producing nitrogen while decomposing as additive
  • Method for rapidly combusting and synthesizing silicon nitride powder by using foaming agent capable of producing nitrogen while decomposing as additive

Examples

Experimental program
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Effect test

Embodiment 1

[0032] A method for rapidly burning and synthesizing silicon nitride powder with a blowing agent capable of generating nitrogen when decomposed as an additive, comprising the steps of:

[0033] 1) Weigh the raw materials according to the weight ratio of silicon powder: silicon nitride powder: AC foaming agent with a purity >99% of 49.5: 49.5: 1;

[0034] 2) Mix and grind the prepared raw materials on a vibrating grinder for 1 hour. After grinding, the powder is sieved to control the relative density of the powder base to 40%, and then put it into a container;

[0035] 3) Put the container into a combustion synthesis reaction device with a cooling water jacket, place a spiral tungsten wire and titanium powder at one end of the powder blank as an ignition source; after vacuuming, fill the combustion synthesis reaction device with nitrogen, Until the pressure reaches 2 MPa; heat the tungsten wire to ignite the titanium powder, and induce the combustion synthesis reaction of the p...

Embodiment 2

[0039] A method for rapidly burning and synthesizing silicon nitride powder with a blowing agent capable of generating nitrogen when decomposed as an additive, comprising the steps of:

[0040] 1) Weigh the raw materials according to the weight ratio of silicon powder:AC blowing agent with a purity >99% of 90:10;

[0041] 2) Mix and grind the prepared raw materials on a vibrating grinder for 1.5 hours. After grinding, the powder is sieved to control the relative density of the powder base to 40%, and then put it into a container;

[0042] 3) Put the container into a combustion synthesis reaction device with a cooling water jacket, place a spiral tungsten wire and titanium powder at one end of the powder blank as an ignition source; after vacuuming, fill the combustion synthesis reaction device with nitrogen, Until the pressure reaches 4.0 MPa; energize and heat the tungsten wire to ignite the titanium powder, and induce the combustion synthesis reaction of the powder system; ...

Embodiment 3

[0046] A method for rapidly burning and synthesizing silicon nitride powder with a blowing agent capable of generating nitrogen when decomposed as an additive, comprising the steps of:

[0047] 1) Weigh the raw materials according to the weight ratio of silicon powder: silicon nitride powder: AC foaming agent with a purity >99%: DPT foaming agent with a purity >99%: 47: 47: 3:3;

[0048] 2) Mix and grind the prepared raw materials on a vibrating grinder for 1.5 hours. After grinding, the powder is sieved to control the relative density of the powder to 50%, and then put it into a container;

[0049] 3) Put the container into a combustion synthesis reaction device with a cooling water jacket, place a spiral tungsten wire and titanium powder at one end of the powder blank as an ignition source; after vacuuming, fill the combustion synthesis reaction device with nitrogen, Until the pressure reaches 3 MPa; heat the tungsten wire to ignite the titanium powder, and induce the combus...

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Abstract

The invention discloses a method for rapidly combusting and synthesizing silicon nitride powder by using a foaming agent capable of producing nitrogen while decomposing as an additive, which comprises the following steps: in the rapid combustion and synthesis process of silicon nitride, the foaming agent capable of producing nitrogen while decomposing is taken as an auxiliary agent; the foaming agent possesses the purity greater than 99% and comprises an azo compound, a nitroso compound, a sulfohydrazide compound and the like. The method of the invention has the following beneficial effects: 1) the used foaming agent has the advantages of no toxicity, constant color, no odor, no pollution and insolubility in common solvents; 2) the foaming agent of the invention has the advantages of highgas evolution, small particles and good dispersibility; 3) the foaming agent is selected as nitrogen source, so that production security is increased, and the raw material cost is reduced; and 4) thefoaming agent discharges a lot of heat while decomposing, so that the combustion and synthesis reaction can be carried out with a faster reaction rate, the instability problem during the combustion process can be solved.

Description

technical field [0001] The present invention relates to a method for combustion synthesis (also known as self-propagating high-temperature synthesis) of silicon nitride powder, in particular to a method for rapidly burning and synthesizing silicon nitride powder with a foaming agent capable of generating nitrogen when decomposed as an additive, which belongs to silicon nitride The technical field of powder preparation. Background technique [0002] Silicon nitride ceramics is a typical representative of advanced structural ceramic materials. Due to its excellent high-temperature mechanical properties, thermal properties and chemical stability, it can be widely used in machinery, chemical industry, aerospace and other fields. Silicon nitride powder is used as a raw material for the production of silicon nitride ceramic products, and its high price severely limits the amount and scale of silicon nitride ceramics. Therefore, the research and development of low-cost silicon nit...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C01B21/068
Inventor 陈义祥林志明李江涛刘光华崔猛
Owner TECHNICAL INST OF PHYSICS & CHEMISTRY - CHINESE ACAD OF SCI
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