Method for preparing silicon carbide whisker/aluminium oxide composite ceramic powder using natural kaolin

A technology for silicon carbide whiskers and composite ceramics is applied in the field of in-situ synthesis of natural kaolin to prepare silicon carbide whiskers/alumina composite ceramic powder, which can solve the problems that composite ceramics cannot give full play to their composite advantages, difficult to prepare, and expensive raw materials, etc. Achieve ideal morphology and two-phase uniformity, easy process control, and simple synthesis process.

Inactive Publication Date: 2006-08-23
GUILIN UNIVERSITY OF TECHNOLOGY
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The raw materials are expensive, the preparation is not easy, and the cost is high; in addition, the mechanical mixing possibility of silicon carbide whiskers, especially nano-scale and sub-micron-scale silicon carbide crystals and alumina is very poor, and it is difficult to achieve uniformity of two phases on a smaller scale sex
Composite ceramics prepared by mechanically mixing raw materials of the two cannot give full play to the composite advantages

Method used

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  • Method for preparing silicon carbide whisker/aluminium oxide composite ceramic powder using natural kaolin
  • Method for preparing silicon carbide whisker/aluminium oxide composite ceramic powder using natural kaolin
  • Method for preparing silicon carbide whisker/aluminium oxide composite ceramic powder using natural kaolin

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0012] Weigh 272g of kaolin concentrate powder and 144g of carbon black, put them into a ball mill jar, and put in grinding balls (the ratio of material to ball is 1:5); after ball milling for 2 hours, take out the sample and place it in an oven to dry at 100°C for 2 hours; Put the high-alumina crucible into the atmosphere furnace, evacuate to <10Pa, close the vacuum system, fill with argon to an atmospheric pressure, open the exhaust valve and insert the exhaust pipe into the water seal; the temperature rise rate is 10°C per minute Raise the temperature to 1550°C and keep it warm for 2 hours. During this period, due to the rise in temperature, the gas in the furnace will expand, and some gas will be discharged through the water seal, but the air pressure in the furnace is basically constant at about one atmospheric pressure; after the heat preservation is over, cut off the power and turn off the The exhaust valve (to prevent the water seal from sucking back) will cool naturall...

Embodiment 2

[0014] Weigh 272g of kaolin concentrate powder and 144g of graphite, put them into a ball mill jar, and put in grinding balls (the ratio of material to ball is 1:5); after ball milling for 2 hours, take out the sample and place it in an oven to dry at 100°C for 2 hours; Put the high-alumina crucible into the atmosphere furnace, evacuate to <10Pa, close the vacuum system, fill it with argon to an atmospheric pressure, open the exhaust valve and insert the exhaust pipe into the water seal; heat up at a rate of 10°C per minute to 1500°C and keep warm for 2 hours. During this period, due to the increase in temperature, the gas in the furnace will expand, and some gas will be discharged through the water seal, but the air pressure in the furnace is basically constant at about one atmosphere; after the heat preservation is over, cut off the power supply and close the exhaust The gas valve (to prevent the water seal from sucking back) is naturally cooled slowly with the furnace; when ...

Embodiment 3

[0016] Weigh 272g of kaolin concentrate powder and 150g of activated carbon, put them into a ball mill jar, and put in grinding balls (the ratio of material to ball is 1:5); after ball milling for 2 hours, take out the sample and place it in an oven to dry at 100°C for 2 hours; Put the high-alumina crucible into the atmosphere furnace, evacuate to <10Pa, close the vacuum system, fill with argon to an atmospheric pressure, open the exhaust valve and insert the exhaust pipe into the water seal; the temperature rise rate is 10°C per minute Raise the temperature to 1450°C and keep it warm for 2 hours. During this period, due to the rise in temperature, the gas in the furnace will expand, and some gas will be discharged through the water seal, but the air pressure in the furnace is basically constant at about one atmospheric pressure; after the heat preservation is over, cut off the power and turn off the The exhaust valve (to prevent the water seal from sucking back) will cool natu...

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Abstract

The present invention discloses process of preparing composite ceramic powder of silico carbide whisker and alumina with natural kaolin. The preparation process includes ball milling and mixing the materials including natural kaolin and carbon source, which may be graphite, carbon black or organic high molecular matter, in the molar ratio of 1 to 3; drying and setting inside high alumina crucible and in furnace, which is first vacuum pumped and then filled with Ar in 1 atm as protecting atmosphere; raising the temperature at 10-15 deg.c/min speed to 1450-1550 deg.c, maintaining for 2-4 hr, and naturally cooling inside the furnace to obtain the composite ceramic powder of silico carbide whisker and alumina in nanometer level or sub-micron level. The present invention has cheap material, simple synthesis process and easy control the process, and the preparation composite ceramic powder has ideal shape and two-phase homogeneity.

Description

technical field [0001] The invention relates to a method for preparing silicon carbide whisker / alumina composite ceramic powder by in-situ synthesis of natural kaolin. The prepared silicon carbide whisker / alumina composite powder can be used to prepare SiC(w) reinforced Al 2 o 3 The preparation of ceramic films and blocks is applied to structural parts in the fields of high strength, heat insulation, and anti-corrosion. Background technique [0002] Alumina ceramics are very important high-temperature structural ceramics, which have excellent corrosion resistance and high-temperature strength, but have the disadvantage of high brittleness. In addition, the aluminum oxide material is very sensitive to cracks in itself, especially on the surface, and has low reliability in use. Silicon carbide whisker reinforced alumina ceramics (SiC(w) / Al 2 o 3 ) The research on composite materials is carried out for this problem. Silicon carbide has become one of the best choices for t...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C04B35/565
Inventor 邹正光龙飞顾涛
Owner GUILIN UNIVERSITY OF TECHNOLOGY
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