Preparation method of alpha-phase silicon nitride powder

A technology based on silicon nitride powder and silicon tetrachloride, applied in chemical instruments and methods, nitrogen compounds, inorganic chemistry, etc., can solve the problems of unsuitability for large-scale production, strict raw material requirements, high cost, etc. control, uniform grain size distribution, and the effect of meeting production needs

Active Publication Date: 2018-04-24
浙江英德赛半导体材料股份有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

These methods have high costs, strict requirements on raw materials, and low yields, and are not suitable for large-scale production.

Method used

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  • Preparation method of alpha-phase silicon nitride powder
  • Preparation method of alpha-phase silicon nitride powder
  • Preparation method of alpha-phase silicon nitride powder

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0050] Example 1, preparation of α-phase silicon nitride powder

[0051] according to figure 2 The flow chart shown in the preparation of α-phase silicon nitride powder, the specific steps are as follows:

[0052] (1) Control the temperature in the reactor to be -45°C, place a mixed solution of 200 volumes of toluene and 200 volumes of xylene and 100 volumes of liquid ammonia in figure 1 In the reaction kettle shown, let it stand for stratification; mix 5 volumes of silicon tetrachloride with 95 volumes of toluene, put the mouth of the silicon tetrachloride feeding tube into the toluene layer in the reaction kettle, and pass it into the feeding tank The mixture of silicon tetrachloride and toluene was injected into the toluene layer by nitrogen pressure, and the feeding rate was controlled at 3mL / min, so that silicon tetrachloride diffused to the liquid phase interface of toluene and liquid ammonia, and the stirring paddle was continuously stirred. The rotation speed is 70 ...

Embodiment 2

[0056] Example 2, preparation of α-phase silicon nitride powder

[0057] according to figure 2 The flow chart shown in the preparation of α-phase silicon nitride powder, the specific steps are as follows:

[0058] (1) Control the temperature in the reactor to be -50°C, place a mixed solution of 300 volumes of toluene and 100 volumes of xylene and 100 volumes of liquid ammonia in figure 1 In the reaction kettle shown, let it stand for stratification; mix 10 volumes of silicon tetrachloride with 90 volumes of toluene, put the mouth of the silicon tetrachloride feeding tube into the toluene layer in the reaction kettle, and pass it into the feeding tank The mixed solution of silicon tetrachloride and toluene was injected into the toluene layer by means of nitrogen pressure, and the feeding rate was controlled at 5mL / min, so that the silicon tetrachloride diffused to the liquid phase interface of toluene and liquid ammonia, and the stirring paddle continued to stir. The rotatio...

Embodiment 3

[0062] Example 3, preparation of α-phase silicon nitride powder

[0063] according to figure 2 The flow chart shown in the preparation of α-phase silicon nitride powder, the specific steps are as follows:

[0064] (1) Control the temperature in the reactor to be -55°C, place 400 volumes of toluene and 100 volumes of liquid ammonia in figure 1 In the reaction kettle shown, let it stand for stratification; mix 10 volumes of silicon tetrachloride with 90 volumes of toluene, put the mouth of the silicon tetrachloride feeding tube into the toluene layer in the reaction kettle, and pass it into the feeding tank The mixed solution of silicon tetrachloride and toluene was injected into the toluene layer by means of nitrogen pressure, and the feeding rate was controlled at 5mL / min, so that the silicon tetrachloride diffused to the liquid phase interface of toluene and liquid ammonia, and the stirring paddle continued to stir. The rotation speed is 100 rpm, silicon tetrachloride and ...

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Abstract

The invention discloses a preparation method of alpha-phase silicon nitride powder. The preparation method comprises the following steps: (1) reacting silicon tetrachloride with liquid ammonia in a two-liquid-phase interface of an organic solvent and the liquid ammonia to obtain a precursor which is silylimine, wherein the organic solvent is methylbenzene or a mixture of the methylbenzene and dimethylbenzene; (2) carrying out thermal decomposition on the silylimine to obtain non-shaped silicon nitride powder; and (3) carrying out crystallization treatment on the non-shaped silicon nitride powder in step (2) to obtain the alpha-phase silicon nitride powder. In the method, silicon tetrachloride reacts with the liquid ammonia on the two-liquid-phase interface of the organic solvent and the liquid ammonia, the silicon tetrachloride is diluted at low temperature, the reaction rate can be reduced by control over feeding speed, synthesis of the precursor can be controlled effectively, the circumstance that aggregates are formed by the precursor is avoided, the reaction area is expanded by interfacial reaction, and the speed of NH4Cl dissolved in the liquid ammonia is increased. The prepared alpha-Si3N4 powder is controllable in crystal form and morphology, grain sizes are distributed uniformly, a technological process is simple, and production requirements can be met.

Description

technical field [0001] The invention relates to a method for preparing silicon nitride powder by a precursor method, in particular to a method for preparing α-phase silicon nitride powder, and belongs to the field of inorganic non-metallic powder materials. Background technique [0002] Among high-temperature engineering materials, silicon nitride ceramics have excellent performance. It has good mechanical properties, high hardness, high elastic modulus; stable thermal properties, small thermal expansion coefficient, high temperature resistance; good chemical stability, not easy to be corroded; good insulation, etc. It has been used more and more in chemical corrosion-resistant devices, high-temperature and wear-resistant parts of engines, automotive bearings, cutting tools, etc. [0003] There are two types of sintered primary powders of silicon nitride ceramics, α phase and β phase. The initial powder has an important influence on the structure and mechanical properties ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C04B35/584C04B35/626C01B21/068B01J19/18B01J4/00
CPCB01J4/001B01J4/008B01J19/0013B01J19/0066B01J19/18B01J2219/00087C01B21/068C01P2002/72C01P2004/03C01P2004/10C01P2004/54C01P2004/62C01P2006/12C04B35/584C04B35/626C04B2235/3878
Inventor 谢志鹏胡尊兰
Owner 浙江英德赛半导体材料股份有限公司
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