Preparation technology for recrystallizing carborundum product

A technology for recrystallized silicon carbide and silicon carbide powder is applied in the field of preparation of recrystallized silicon carbide products, which can solve the problems of high price, high recrystallization temperature, limited application, etc., to expand the application market, good high temperature strength, Complete effect of recrystallization process

Inactive Publication Date: 2007-07-11
HUNAN UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Due to its high recrystallization temperature, high technical difficulty, and high price, the current average price of domestic recrystallized silicon carbide products is about 200,000 yuan / ton, which largely limits its application in wider fields

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0030] Embodiment 1: by weight component, get 40 order silicon carbide 30, 100 order silicon carbide 20, 1200 order silicon carbide 16, 3000 order silicon carbide 18, silicon powder 10, carbon powder 5, sodium methylcellulose 1.5; Add water 70. The above-mentioned raw materials were ball-milled and dispersed in a ball mill for 6 hours to obtain a flowable uniform slurry, which was poured into a plaster mold. After demoulding and drying, the two ends of the product are connected with graphite electrodes, and the surrounding is filled with a mixed powder of carbon powder and silicon carbide powder. The two graphite electrodes are energized, and the green body is used for self-heating. When the sintering temperature reaches 1500°C, the temperature is kept for 3 hours; the voltage of the electric furnace is adjusted to make the product continue to heat up to 2500°C. Let it cool down to room temperature naturally. The prepared recrystallized silicon carbide product has a purity o...

Embodiment 2

[0031] Embodiment 2: By weight components, get 46 mesh silicon carbide 40, 120 mesh silicon carbide 25, 1200 mesh silicon carbide 15, 3000 mesh silicon carbide 10, silicon powder 6, carbon powder 3, polyvinyl alcohol 0.3; add water 5 . After the above-mentioned raw materials are fully mixed and uniform, they are molded. After drying, the two ends of the product are connected with graphite electrodes, and the surrounding is filled with a mixed powder of carbon powder and silicon carbide powder. The two graphite electrodes are energized, and the green body is used for self-heating. When the sintering temperature reaches 1600 ° C, it is kept for 2 hours; the voltage of the electric furnace is adjusted to make the product continue to heat up to 2500 ° C. Let it cool down to room temperature naturally. The prepared recrystallized silicon carbide product has a purity of 99% and a density of 2.72g / cm 3 .

Embodiment 3

[0032] Embodiment 3: by weight components, get 60 mesh silicon carbide 35, 120 mesh silicon carbide 25, 1200 mesh silicon carbide 10, 3000 mesh silicon carbide 5, silicon powder 16, carbon powder 9, polyvinyl alcohol 0.2; add water 3 . After the above raw materials are fully mixed and uniform, isostatic pressing is performed. After drying, the two ends of the product are connected with graphite electrodes, and the surrounding is filled with a mixed powder of carbon powder and silicon carbide powder. The two graphite electrodes are energized, and the green body is used for self-heating. When the sintering temperature reaches 1700 ° C, it is kept for 2 hours; the voltage of the electric furnace is adjusted to make the product continue to heat up to 2500 ° C. Let it cool down to room temperature naturally. The prepared recrystallized silicon carbide product has a purity of 99% and a density of 2.70g / cm 3 .

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Abstract

The invention discloses a making technique of recrystallizing carborundum product, which comprises the following steps: blending carborundum powder with certain grain grade with purity over 96% and silicon powder and carbon powder evenly; adding a little of adhesive; moulding according to normal technique; placing green compact in the sintering stove; connecting graphite electrode on two ends; filling the composite powder of carborundum powder and carbon powder around two ends; supplying power for graphite electrode; utilizing the conductivity of mould to realize itself heating sintering; insulating 1-4h after the temperature reaches to 1400-1700 deg. c; heating continuously to 2500 deg. c; insulating 3-10h; cooling the stove to indoor temperature naturally; obtaining the high-purity recrystallizing carborundum product.

Description

technical field [0001] The invention relates to material preparation technology, and further refers to a preparation technology of recrystallized silicon carbide products. Background technique [0002] At present, the preparation method of recrystallized silicon carbide products is to mix coarse silicon carbide with very fine silicon carbide powder, and then vaporize the fine silicon carbide in vacuum induction sintering at a high temperature above 2300°C. The contact necks of the coarse grains re-coagulate so that the coarse SiC grains bond to each other. Since recrystallized silicon carbide has no other binding phases and impurities, the purity depends on the purity of silicon carbide powder, which can reach 99%, and they are all high-temperature stable silicon carbide with good crystallization, so they have excellent high-temperature mechanical properties. The bending strength increases with the increase of temperature, and the strength at 1400 ° C is about 20% higher th...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C04B35/573C01B31/36
Inventor 肖汉宁高朋召
Owner HUNAN UNIV
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