Preparation method of low-thermal-conductivity silicon-nitride-bonded silicon carbide porous ceramic

A porous ceramic, low thermal conductivity technology, used in ceramic products, applications, household appliances, etc., can solve the problems of low thermal conductivity, low density, poor corrosion resistance, etc., achieve low density thermal conductivity, ultra-low thermal conductivity, The effect of excellent corrosion resistance

Active Publication Date: 2013-04-24
SINOSTEEL LUOYANG INST OF REFRACTORIES RES
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

Among them, carbon blocks and silicon nitride combined with silicon carbide bricks are commonly used corrosion-resistant side lining materials in the field of aluminum electrolytic cells, but their thermal conductivity is high and heat loss is serious; aluminum silicate fiberboard has low density, low thermal conductivity, good heat preservation The effect is good, but the fiberboard is easy to react with F, Na and other substances during use, resulting in the deterioration of the fiber structure, damaging its thermal insulation performance and even causing the fiberboard to be pulverized
[0003] The current technical solution is to simply

Method used

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  • Preparation method of low-thermal-conductivity silicon-nitride-bonded silicon carbide porous ceramic

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0019] First, add 100 g of metal silicon powder, 80 g of water, 0.6 g of ammonium tripolyphosphate, 2 g of acrylamide, and 0.2 g of methylenebisacrylamide into a ball milling tank, and ball mill for 3 hours at a speed of 150 r / min to obtain a stable slurry. Add 3.7 g of sodium lauryl sulfate, 5.48 g of ammonium persulfate, and 0.05 g of N,N,N',N'-tetramethylethylenediamine into the slurry, and stir at a speed of 190r / min for 1.5h to obtain a Bubble slurry. It is poured into a mold, left to solidify and released from the mold. The green body obtained was first dried in a constant temperature and humidity box with a humidity of 50% and a temperature of 55oC for 55h, and then moved to an ordinary oven at 80oC for 48h. The dried green body is first kept in an air atmosphere furnace at 400oC for 5 hours for debinding, and then transferred to a nitrogen atmosphere furnace for 8 hours at 1400oC for nitriding sintering. The resulting porous ceramics have a bulk density of 0.7 g / cm ...

Embodiment 2

[0021] First, add 90g of metal silicon powder, 10g of silicon carbide powder, 60g of water, 1.5g of sodium tripolyphosphate, 17g of acrylamide, and 1.7g of methylenebisacrylamide into the ball milling tank, and ball mill for 1 hour at a speed of 200r / min to obtain a stable slurry. Add 9.01g of sodium dodecylbenzenesulfonate, 1.7g of ammonium persulfate, 0.1g of N,N,N',N'-tetramethylethylenediamine to the slurry, and stir at 80r / min for 2h to obtain Foam paste. It is poured into a mold, left to solidify and released from the mold. The obtained body was first dried in a constant temperature and humidity box with a humidity of 80% and a temperature of 30oC for 60h, and then moved to an ordinary oven at 85oC for 42h. The dried body is firstly kept in an air atmosphere furnace at 600oC for 2 hours for debinding, and then transferred to a nitrogen atmosphere furnace and held at 1300oC for 10 hours for nitriding sintering. The bulk density of the resulting porous ceramics is 0.49 ...

Embodiment 3

[0023] First, add 80g of metal silicon powder, 20g of silicon carbide powder, 120g of water, 1.3g of ammonium hexametaphosphate, 20g of methacrylamide, and 2.0g of methyl acryl acrylate into the ball milling tank, and ball mill for 5 hours at a speed of 120r / min to obtain stabilize the slurry. Add 4.3g of ammonium laurylsulfate, 1.22g of ammonium persulfate, 0.07g of N,N,N',N'-tetramethylethylenediamine into the slurry, and stir at 210r / min for 1h to obtain foaming slurry. It is poured into a mold, left to solidify and released from the mold. The obtained body was first dried in a constant temperature and humidity box with a humidity of 60% and a temperature of 70oC for 50h, and then moved to a common oven at 100oC for 32h. The dried green body is first kept in an air atmosphere furnace at 500oC for 5 hours for debinding, and then transferred to a nitrogen atmosphere furnace for 2 hours at 1500oC for nitriding sintering. The bulk density of the resulting porous ceramics is ...

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Abstract

The invention relates to a preparation method of low-thermal-conductivity silicon-nitride-bonded silicon carbide porous ceramic. The preparation process can be realized with the steps that: (1) ceramic powder, water, a dispersing agent, a monomer used in gel-casting molding, and a crosslinking agent are subjected to mixing and ball milling, such that uniform slurry is obtained; (2) a proper amount of a foaming agent is added into the slurry, and the slurry is mechanically stirred, such that foam slurry is obtained; proper amounts of an initiator and a catalyst are sequentially added into the foam slurry, and the foam slurry is rapidly casted into a mold; (3) when the slurry is cured, de-molding is carried out, such that a blank is obtained; and the blank is sequentially dried in a constant-temperature constant-humidity chamber and in a common baking oven; (4) the dried blank is sequentially subjected to de-binding in an air atmosphere furnace and sintering in a nitrogen atmosphere furnace, such that silicon-nitride-bonded silicon carbide porous ceramic is obtained. The method provided by the invention is characterized in that, with the foaming technology, enough gap space is maintained in the inside after the blank is molded; with the fiber structure produced during silicon nitridation, the prepared product has low density, ultralow thermal conductivity, and good corrosion resistance. The ceramic can be used as an energy-saving aluminum electrolysis cell periphery insulation material.

Description

technical field [0001] The present invention relates to a kind of preparation method of silicon nitride combined with silicon carbide porous ceramics with low thermal conductivity, more precisely relates to a kind of silicon / silicon carbide porous body first prepared by gel injection molding process combined with foaming method, and then treated with nitrogen The invention relates to a preparation method for finally obtaining silicon nitride combined with silicon carbide porous ceramics through chemical sintering, and belongs to the field of porous ceramics preparation. Background technique [0002] For a long time, because silicon nitride combined with silicon carbide has excellent properties such as good cryolite melt erosion resistance, good corrosion resistance, and good thermal shock resistance, it is currently the most commonly used side lining material for prebaked aluminum electrolytic cells. In recent years, due to the aggravation of the energy crisis and my country...

Claims

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Application Information

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IPC IPC(8): C04B38/10C04B35/565C04B35/584C04B35/622
Inventor 王刚袁波李红霞韩建燊万龙刚
Owner SINOSTEEL LUOYANG INST OF REFRACTORIES RES
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