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Silicon nitride material and preparation method of heat insulating disc cover prepared from same

A technology of silicon nitride and nano-silicon nitride, which is applied in the field of heat insulation disk cover preparation, can solve the problems of large thermal expansion coefficient, impossibility of popularization and long delivery period, and achieve uniform density distribution, short diffusion distance and high quality Improved effect

Inactive Publication Date: 2012-07-04
BEIJING SINOMA SYNTHETIC CRYSTALS CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Quartz will undergo a phase transition at around 1200°C, which will cause a large volume change. Due to its large thermal expansion coefficient, alumina cannot withstand such a high temperature gradient for a long time and frequently. These two reasons lead to frequent replacement of the heat insulation disk cover.
Although imported silicon nitride heat shields have a long service life, the price is too high and the delivery period is long, so they cannot be widely used in the domestic market.

Method used

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  • Silicon nitride material and preparation method of heat insulating disc cover prepared from same
  • Silicon nitride material and preparation method of heat insulating disc cover prepared from same

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preparation example Construction

[0039] figure 1 The flow chart of the preparation method of the heat-insulating disc cover made of the silicon nitride material according to the present invention, such as figure 1 As shown, the preparation method of the heat-insulating disk cover made of the silicon nitride material described in the invention comprises the following steps:

[0040] 1) Weigh the raw materials according to the appropriate weight ratio, and mix them evenly by ball milling in the medium;

[0041] 2) drying the mixed material to make base material;

[0042] 3) After pressing and forming, a tubular green body is obtained;

[0043] 4) Processed to appropriate size on a lathe;

[0044] 5) Put the processed biscuit into the sintering furnace and fill it with nitrogen for sintering;

[0045] 6) Stop heating, cool down, open the furnace door under normal pressure to cool naturally, and get the blank;

[0046] 7) Process the blank on the grinding machine to obtain the finishe...

Embodiment 1

[0048] Weigh each raw material according to the following weight percentage: 87.5% of silicon nitride (average particle size of 0.1-5μm), 7% of nano-silicon nitride (average particle size of 2 o 3 (average particle size 2 o 3 6%, tungsten carbide (average particle size <5μm) is 0.5%, put it into a high-strength alumina ceramic container, add solvent high-purity ethanol, put silicon nitride grinding balls, roller ball mill for 30 hours, mix the materials into Dry it in an oven at a temperature of 120° C., sieve out impurities after drying, put it into a rubber mold for cold isostatic pressing at a molding pressure of 180 MPa, and obtain a green body. The biscuit is machined to precise dimensions on a lathe and then placed in a sintering furnace for sintering under nitrogen atmosphere with elevated temperature and pressure. The specific heating process is as follows: when the temperature rises to 1350°C, the pressure is increased to 0.4MPa and kept for 30 minutes; when the temp...

Embodiment 2

[0051] Weigh each raw material according to the following weight percentage: silicon nitride 65%, nano-silicon nitride 15%, sintering aid: Al 2 o 3 8%, La 2 o 3 (average particle size<5μm) 7%, tungsten carbide (average particle size<5μm) is 5%, add solvent high-purity ethanol, add abrasive polyethylene glycol with 1% of the total mass of raw materials, put alumina grinding balls, After roller milling for 40 hours, the mixed material was dried in an oven at a temperature of 80° C., and the sundries were sieved after drying. The base material is put into a polyurethane mold for cold isostatic pressing with a molding pressure of 200 MPa to obtain a green body. The biscuit is machined to precise dimensions on a lathe and then placed in a sintering furnace for sintering under nitrogen atmosphere with elevated temperature and pressure. The specific heating process is as follows: when the temperature rises to 1400°C, the pressure is increased to 1MPa and kept for 30 minutes; w...

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Abstract

The invention relates to a silicon nitride material and a preparation method of a heat insulating disc cover prepared from the same. The silicon nitride material consists of the following raw materials in percentage by weight: 65-87.5 percent of silicon nitride, 5-15 percent of nano-silicon nitride, 8-15 percent of a sintering aid and 0.5-5 percent of tungsten carbide; and the preparation method of the heat insulating disc cover prepared from the silicon nitride material comprises the following steps of: weighing the silicon nitride, nano-silicon nitride, sintering aid and tungsten carbide according to the percentage by weight, performing ball milling and mixing uniformly; drying a mixed material to obtain a substrate; performing press molding to obtain a cylindrical biscuit; processing to a proper size on a lathe; putting the processed biscuit into a sintering furnace, and charging nitrogen gas for sintering; stopping heating, cooling, opening a furnace door under the normal pressure, and cooling naturally to obtain a blank; and performing end face processing on the blank on a grinding machine to obtain a finished product.

Description

technical field [0001] The invention relates to a silicon nitride material and a method for preparing a heat-insulating disk cover made of the silicon nitride material, and belongs to the technical field of inorganic chemical materials. Background technique [0002] The international photovoltaic industry is developing rapidly, and the polysilicon market is in the ascendant. At present, along with the production of polysilicon, the treatment of silicon tetrachloride in the process tail gas has become increasingly prominent, which may cause serious environmental pollution problems. At the same time, as the market competition intensifies, manufacturers continue to pay attention to the recycling of silicon tetrachloride. [0003] As a treatment device for process tail gas, the polysilicon hydrogenation furnace has very harsh process conditions. Silicon tetrachloride needs to react at a high temperature of 1200°C, and the temperature in the furnace may reach 1400°C ins...

Claims

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Application Information

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IPC IPC(8): C04B35/584C04B35/622
Inventor 茹敏朝徐鹏张伟儒喻显扬
Owner BEIJING SINOMA SYNTHETIC CRYSTALS CO LTD
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