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Method for preparing gamma-AlON ceramic powder based on carbon thermal reduction nitridation

A ceramic powder and nitriding technology, which is applied in the field of rapid preparation of γ-AlON transparent ceramic powder, can solve the problems of slow synthesis process, expensive raw materials, and incomplete reaction, and achieve uniform and fine particle size, complete reaction transformation, and inhibition The effect of grain growth

Inactive Publication Date: 2009-09-16
WUHAN UNIV OF TECH
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  • Abstract
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Problems solved by technology

The fine and high-purity AlN powder required in the reaction raw materials is a test for cost expenditure, and the high temperature and long-term insulation also greatly restrict the industrial application of this method
2) The chemical vapor deposition method is mostly used to prepare γ-AlON thin films or coatings. For example, spinel γ-AlON coatings can be coated on Si substrates at 900 °C; this method has the advantages of high purity of synthetic products and small particle size. etc., but the synthesis process is slow, the raw materials are expensive, and the application range is limited
3) Self-propagating high-temperature synthesis method, which is to heat metal aluminum powder in the air and apply appropriate air pressure to synthesize γ-AlON. The reaction equation is: Al(l)+Air→γ-AlON(s ) (≥1500°C); the preparation of γ-AlON by the self-propagating method has the advantages of fast reaction speed and low cost, but the synthesis of γ-AlON depends on the applied air pressure and how to control the high temperature melting of Al, so the reaction is not easy to complete and The impurity content is high; in addition, the process parameters of this method are not easy to control, and the repeatability is poor
The disadvantage is that the reaction process is slow, the time is long, and there are many factors affected
[0006] From the above analysis, it can be seen that the existing methods for preparing γ-AlON transparent ceramic powders by carbothermal reduction and nitriding have disadvantages such as low synthesis efficiency, high energy consumption, and high time consumption, and the synthesized γ-AlON ceramic powders often have coarse particles and low activity. or high impurity content

Method used

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  • Method for preparing gamma-AlON ceramic powder based on carbon thermal reduction nitridation
  • Method for preparing gamma-AlON ceramic powder based on carbon thermal reduction nitridation
  • Method for preparing gamma-AlON ceramic powder based on carbon thermal reduction nitridation

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Effect test

Embodiment 1

[0025] The selected mass ratio is γ-Al 2 o 3 :starch=4:1. First weigh γ-Al in proportion 2 o 3 Add 8g of powder and 2g of starch, add 100ml of distilled water, and use alumina balls as the medium to ball mill and mix for 24 hours to obtain a slurry; take out the slurry and dry it under vacuum at 100°C to evaporate the water; put the dried powder in Under argon atmosphere, heat treatment in a tube furnace at 400°C for 12 hours to dehydrate to form γ-Al 2 o 3 and carbon precursor powder; the precursor powder is placed in a crucible, the crucible is placed in a graphite reactor, and the graphite reactor is placed in a high-current reaction synthesis device, nitrogen gas is introduced and the flow of the atmosphere is maintained throughout the heating process The synthesis temperature is 1500°C, the heating rate is 50°C / min, and the heat preservation is 50min to obtain the carbon-containing mixed powder; after cooling down, the carbon-containing mixed powder is taken out and ...

Embodiment 2

[0027] The selected mass ratio is γ-Al 2 o 3 :starch=10:2.6. First weigh γ-Al in proportion 2 o 3 Add 10g of powder and 2.6g of starch, add 100ml of absolute ethanol, and use alumina balls as the medium to ball mill and mix for 48 hours to obtain a slurry; take out the slurry and dry it under vacuum at 70°C to volatilize the ethanol; the dried powder Under argon atmosphere, heat treatment in a tube furnace at 450°C for 10h to dehydrate to form γ-Al 2 o 3 and carbon precursor powder; the former precursor powder is placed in a crucible, the crucible is placed in a graphite reactor, and the graphite reactor is placed in a high-current reaction synthesis device, nitrogen gas is introduced and the flow of the atmosphere is maintained throughout the heating process The synthesis temperature is 1550°C, the heating rate is 100°C / min, and the heat preservation is 35 minutes to obtain the carbon-containing mixed powder; after cooling down, the carbon-containing mixed powder is take...

Embodiment 3

[0029] The selected mass ratio is γ-Al 2 o 3 :starch=4:1. First weigh γ-Al in proportion 2 o 3 Add 8g of powder and 2g of starch, add 100ml of distilled water and mix evenly (using alumina balls as the medium for ball milling and mixing for 36h) to obtain a slurry; take out the slurry and dry it under vacuum at 100°C to volatilize the water; the dried powder The body was heat-treated in a tube furnace at 500 °C for 6 h in an argon atmosphere to form γ-Al 2 o 3 and carbon precursor powder; the former precursor powder is placed in a crucible, the crucible is placed in a graphite reactor, and the graphite reactor is placed in a high-current reaction synthesis device, nitrogen gas is introduced and the flow of the atmosphere is maintained throughout the heating process The synthesis temperature is 1600°C, the heating rate is 200°C / min, and the heat preservation is 30 minutes to obtain the carbon-containing mixed powder; after cooling down, the carbon-containing mixed powder i...

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Abstract

The invention relates to a method for quickly preparing gamma-AlON ceramic powder. A method for preparing gamma-AlON ceramic powder based on carbon thermal reduction nitridation is characterized in that the method includes the following steps: 1) selection of raw materials: alumina and soluble starch are selected according to the mass ratio of 4:1 to 7:1 between alumina and soluble starch, wherein the alumina is alpha-Al2O3 or gamma-Al2O3; distilled water or absolute ethyl alcohol is selected for preparation according to the mass ratio of 33: 1 to 50: 1 between distilled water or absolute ethyl alcohol and soluble starch; 2) preparation of precursor powder; 3) quick nitridation; 4) low-temperature decarbonization; 5) quick synthesis: the mixed powder after decarbonization in step 4 is disposed in a graphite reactor and rapidly heated to the temperature of 1650 to 1800 DEG C with a temperature increasing speed of 100 to 500 DEG C per minute, and the holding time is 5 to 20 minutes so that the gamma-AlON ceramic powder is obtained. The method has the characteristics of quick synthesis speed and high efficiency, and the prepared gamma-AlON ceramic powder has high purity and tiny particle size.

Description

technical field [0001] The invention relates to a rapid preparation method of gamma-AlON transparent ceramic powder, which belongs to the field of synthesis and processing of ceramic material powder. Background technique [0002] γ-AlON is Al 2 o 3 -A stable solid solution in AlN binary system, it has good high temperature resistance, thermal shock stability and corrosion resistance, it is an ideal high temperature structural ceramics and refractory materials. In addition, because of its excellent optical properties, γ-AlON ceramics can be widely used as optical transparent materials in optical windows and covers. However, in order to prepare γ-AlON transparent ceramic products with excellent performance, it is first necessary to obtain high-purity, fine γ-AlON ceramic powder raw materials. [0003] At present, the main methods for preparing γ-AlON ceramic powder are: 1) directly passing Al 2 o 3 It reacts with AlN at high temperature (≥1700°C) in solid phase to form γ-...

Claims

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Application Information

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IPC IPC(8): C04B35/58
Inventor 王皓彭丁王为民傅正义王玉成张清杰
Owner WUHAN UNIV OF TECH
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