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Treatment method of silicon powder for molten silicon infiltration

A processing method and technology of silicon powder, applied in the field of inorganic materials, can solve the problems of reducing the pore size, reducing the permeability of porous bodies, uneven penetration, etc., and achieving the effect of avoiding the blocking of pores by reaction

Pending Publication Date: 2021-12-10
AVIC BEIJING INST OF AERONAUTICAL MATERIALS
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

During the melting process of silicon powder, the peripheral temperature is usually higher, and the melting occurs first. During the heating process, part of it penetrates into the periphery of the porous body first, and reacts with the carbon in the porous body. Silicon carbide reduces the pore size, reduces the gas permeability of the porous body, and causes the problem of uneven penetration or "black core" in some areas

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0022] Adopt technical scheme of the present invention to process the step of silicon powder for fused siliconizing as follows:

[0023] Step 1. Place 500 grams of 10-micron silicon powder in the deposition furnace tooling, use propylene as the carbon source, and deposit a thin layer of cracked carbon on the surface of the silicon powder. The deposition temperature is 950°C and the deposition time is 30 minutes;

[0024] Step 2. Put the carbon-coated silicon powder prepared above into a high-temperature furnace for shelling treatment at a temperature of 1400° C. for 10 minutes to prepare silicon powder containing a silicon carbide shell. The silica powder can be broken at 1600°C to achieve rapid densification of the porous body.

Embodiment 2

[0026] Adopt technical scheme of the present invention to process the step of silicon powder for fused siliconizing as follows:

[0027] Put 500 grams of 10-micron silicon powder in a high-temperature furnace, feed nitrogen gas for high-temperature nitriding treatment, the temperature is 1420°C, and the treatment time is 10 minutes, so that a layer of silicon nitride shell is formed on the surface of the silicon powder. Cracking occurs at 1550°C, realizing rapid densification of the porous body.

Embodiment 3

[0029] Adopt technical scheme of the present invention to process the step of silicon powder for fused siliconizing as follows:

[0030] Step 1. Dissolve 20 grams of phenolic resin in 300 grams of ethanol, then add 500 grams of 10-micron silicon powder into the above solution, and ball mill for 5 hours. Put the above mixture on the release paper and dry it for 5 hours, the drying temperature is 80°C;

[0031] Step 2. Put the dried mixture in a high-temperature furnace for cracking. The cracking temperature is 1000°C for 60 minutes, and then continue to raise the temperature to 1400°C for 10 minutes to prepare a shell containing silicon carbide. of silica fume. The silica powder can be broken at 1600°C to achieve rapid densification of the porous body.

[0032] Using the silicon powder treated in Example 2 to prepare reaction sintered silicon carbide, the porous body is porous carbon formed by resin cracking, the infiltration temperature is 1550°C, the infiltration time is 30...

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Abstract

The invention relates to a treatment method of silicon powder for molten silicon infiltration. The treatment method can be used for preparing reactive sintering silicon carbide, a carbon fiber reinforced silicon carbide-based composite material and a silicon carbide fiber reinforced silicon carbide-based composite material. Traditional reactive siliconizing mostly adopts silicon powder as a siliconizing raw material, and the problems of hole blockage or non-uniform infiltration and the like are easy to occur in the siliconizing process. According to the invention, the silicon powder is pretreated, so a thin shell is formed on the surface of the silicon powder, and the silicon can be broken and quickly enter a porous body by utilizing the volume change effect of the silicon powder in melting and heating processes; and thus, the problems of hole blockage and the like in reaction are avoided, and infiltration efficiency is favorably improved.

Description

technical field [0001] The invention relates to a method for treating silicon powder for fusion siliconizing, which belongs to the field of inorganic materials. Background technique [0002] Reaction fusion siliconizing is a method of melting silicon at high temperature and infiltrating it into a porous body to form a dense material. This method is widely used for reaction sintering silicon carbide and carbon fiber reinforcement due to its advantages of short cycle time and low cost. Silicon carbide composite materials and silicon carbide fiber reinforced silicon carbide composite materials are widely used in civil and military fields. [0003] The traditional reactive siliconizing is to embed the porous body in silicon powder or silicon particles. When heated above the melting point of silicon (1410°C), the silicon will melt, and the liquid silicon will enter the porous body due to the capillary effect, forming a densification. Material. During the melting process of sili...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C04B35/65C04B35/628C04B35/573C04B35/591
CPCC04B35/62834C04B35/62836C04B35/573C04B35/591C04B35/65
Inventor 杨金华焦健刘虎杨瑞艾莹珺
Owner AVIC BEIJING INST OF AERONAUTICAL MATERIALS
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