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Process for preparing silicon carbide crystal whisker

A technology of silicon carbide whiskers and carbonized rice husks is applied in chemical instruments and methods, single crystal growth, crystal growth and other directions, and can solve the problems of easy occurrence of curved crystals, complicated processes, and unguaranteed whisker quality, and achieves The effect of improving the straightness and purity, simplifying the production process, and reducing the amount of carbon residue

Inactive Publication Date: 2006-01-18
NORTHWESTERN POLYTECHNICAL UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0007] The method for preparing silicon carbide whiskers in the above-mentioned documents is not only complicated in process, but also the product is a mixture of whiskers, carbon and firing residues. It is necessary to remove carbon and residues to obtain silicon carbide whiskers. This process is difficult to separate thoroughly. , and whiskers are mixed with powder, prone to bent crystals, which affects the quality of silicon carbide whiskers, and the quality of whiskers cannot be guaranteed

Method used

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  • Process for preparing silicon carbide crystal whisker
  • Process for preparing silicon carbide crystal whisker
  • Process for preparing silicon carbide crystal whisker

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0024] (1) Wash the silt and dust on the rice husk with clean water, and dry it at a temperature of 80°C. The dried clean rice husk is pulverized to 0.1mm particles with a pulverizer for use.

[0025] (2) Put the rice husk particles treated in the step (1) into an alumina sagger, put them into an electric furnace, and use the process of first opening the furnace to burn with a large flame and then closing the furnace for carbonization to carbonize the rice husk particles. The burning time of the large flame is 2 minutes, the carbonization temperature is 700°C, and the heat preservation is 5 hours. The reason why such a carbonization process is adopted is to ensure a suitable ratio of carbon to silicon in the carbonized rice husk particles.

[0026] (3) Put the carbonized rice husk particles into a grinding tank, add distilled water, put them on a fast grinder for 10 minutes, and then dry them at a temperature of 80°C.

[0027] (4) Mix the ground carbonized rice husk particles...

Embodiment 2

[0033] (1) Wash the silt and dust on the rice husk with clean water, and dry it at a temperature of 100°C. The dried clean rice husk is pulverized to 0.5mm particles with a pulverizer for use.

[0034] (2) Put the rice husk particles treated in the step (1) into an alumina sagger, put them into an electric furnace, and use the process of first opening the furnace to burn with a large flame and then closing the furnace for carbonization to carbonize the rice husk particles. The burning time of the large flame is 10 minutes, the carbonization temperature is 650 ℃, and the heat preservation is 3 hours.

[0035] (3) Put the carbonized rice husk particles into a grinding jar, add distilled water, put them on a quick grinder for 15 minutes, and then dry them at a temperature of 100°C.

[0036] (4) Mix the ground carbonized rice husk particles with 2-3% catalyst NaF and 1-2% KF with the carbonized rice husk in a dry method to make a mixture.

[0037] The dry method is to put a cert...

Embodiment 3

[0042](1) Wash the silt and dust on the rice husk with clean water, and dry it at a temperature of 90°C. The dried clean rice husk is pulverized to 0.3mm particles with a pulverizer for use.

[0043] (2) Put the rice husk particles treated in the step (1) into an alumina sagger, put them into an electric furnace, and use the process of first opening the furnace to burn with a large flame and then closing the furnace for carbonization to carbonize the rice husk particles. The burning time of the large flame is 6 minutes, the carbonization temperature is 680 ℃, and the heat preservation is 4 hours.

[0044] (3) Put the carbonized rice husk particles into a grinding tank, add distilled water, put them on a quick grinder for 13 minutes, and then dry them at a temperature of 90°C.

[0045] (4) Mix the ground carbonized rice husk particles and 3% catalyst NaCl with the carbonized rice husk by a wet method, and dry to make a mixture.

[0046] (5) Brush the inner layer of the graphi...

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Abstract

The present invention discloses silicon carbide crystal whisker preparing process and aims at preparing silicon carbide crystal whisker separated from residual carbon powder. The technological scheme is to use carbonized rice hull as both silicon source and carbon source to prepare silicon carbide crystal whisker via carbon fiber induction. The preparation process includes crushing rice hull, carbonizing rice hull at 650-700 deg.c in one first-opening-then-closing process, mixing with catalyst in certain weight ratio, loading the mixed material inside graphite crucible, arranging carbon fiber on the upper part of the mixed material, covering the crucible, setting the crucible inside vertical vacuum furnace with graphite heater, and growing silicon carbide crystal whisker on the carbon fiber white introducing argon for protection. The said process realizes the automatic separation of crystal whisker from residual carbon powder to obtain crystal whisker with high straight crystal rate.

Description

technical field [0001] The invention relates to a method for preparing silicon carbide whiskers. Background technique [0002] The preparation of silicon carbide whiskers can be divided into gas phase and solid phase according to the initial state of raw materials. The solid-phase raw material method is to use different reaction raw materials, add appropriate catalysts, and react in a protective atmosphere to obtain silicon carbide whiskers with different characteristics and specifications. Because this method is more suitable for mass production, it is widely used at present. The preparation of silicon carbide whiskers from carbonized rice husks is a kind of solid-state method. [0003] The document "Preparation of silicon carbide whiskers with rice husks, progress in materials science 1989No2" introduced that Bai Chungen, Institute of Metal Research, Chinese Academy of Sciences, et al. mixed carbonized rice husk ash and Zhongchao carbon black at a weight ratio of 1:2, an...

Claims

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Application Information

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IPC IPC(8): C30B29/36C30B29/62C30B1/00C01B31/36
Inventor 黄凤萍李贺军
Owner NORTHWESTERN POLYTECHNICAL UNIV
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