Preparation method of alumina polycrystalline material block

A kind of technology of alumina and crystal material, applied in the field of preparation of alumina polycrystalline material block

Inactive Publication Date: 2013-08-07
SHANGHAI UNIV
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0007] In view of the defects in the prior art, the purpose of the present invention is to provide a method for preparing alumina polycrystalline block, which can improve the existing alumina cake block Density, in order to improve sapphire production efficiency, reduce production costs, and avoid secondary pollution of raw material powder and cracking of cake blanks during the production of cake materials

Method used

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  • Preparation method of alumina polycrystalline material block
  • Preparation method of alumina polycrystalline material block
  • Preparation method of alumina polycrystalline material block

Examples

Experimental program
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Embodiment 1

[0024] The process and steps of this embodiment are described as follows:

[0025] 1. Commercial high-purity 5N (99.999%) a-Al with two different particle diameters of aluminum alkoxide method 2 O 3 The powder is the raw material, and the ratio of the average particle size is 1:0.15, and the weight ratio is 1:0.1. Specifically, 2400 g for 50 μm large particle size powder, 240 g for 7.5 μm small particle size powder, with a total weight of 2640 g. The theoretical porosity calculated according to the close-packed model is 25.56%.

[0026] 2. Divide the above powder into 4 parts of equal quality, and fill them alternately layer by layer into a self-made rubber bucket mold with a diameter of 150 mm and a height of 130 mm. The rubber mold is always placed on the vibration table during the feeding process, and vibration with a vertical frequency of 500 Hz is applied;

[0027] 3. After the filled rubber mold is sealed, it is placed in an isostatic press and kept under a pressure of 200 MP...

Embodiment 2

[0030] The purity and a-Al of the powder raw materials used in this example 2 O 3 The method and steps for pressing the polycrystalline block are exactly the same as those in Example 1. The difference lies in the use of three different particle diameters of aluminum alkoxide method a-Al 2 O 3 The powder is the raw material, the average particle size is 10 μm, 7 μm and 3 μm respectively (that is, the ratio of the three particle diameters is 1:0.7:0.3), and the weight is respectively 1800 g, 720 g and 108 g (that is, the weight ratio of the three 1:0.4:0.06), the total weight is 2628g. The theoretical void ratio calculated according to the close-packed model is 24.08%.

[0031] After testing, using the methods and steps described in this example, the final diameter is 114 mm, the height is 70 mm, and the density is 3.69 g / cm 3 A-Al 2 O 3 Polycrystalline bulk. The sample has good moldability, no cracks on the surface, and a relative density of 93%.

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Abstract

The invention relates to a preparation method of an alumina polycrystalline material block, and belongs to the technical field of special ceramic preparation process. According to the invention, two or three commercial high-purity 5N (99.999%) alpha-Al2O3 powder materials produced with alcohol-aluminum method are adopted as initial raw materials; with theoretical model calculations and experimental correction, an optimal size ratio and quantity proportions of the powder particles are determined; with a cold isostatic pressing process, the mixed powder material is pressed into a block-shaped material; and through high-temperature sintering, the alpha-Al2O3 polycrystalline block material with a density higher than 3.6g / cm<3> (relative density higher than 90%) is prepared. In the prepared alpha-Al2O3 polycrystalline block material, gaps among large particles are filled by the small-particle-size powder material; and powder contact is increased, such that interaction is increased. Therefore, during the pressing molding and high-temperature sintering processes, cracking is prevented, large-size product can be easily obtained, and the sintering density is higher than alumina cake materials in the market.

Description

technical field [0001] The invention relates to a method for preparing alumina polycrystalline blocks, and belongs to the technical field of special ceramic preparation technology. Background technique [0002] Since the commercialization of white light-emitting diodes (LEDs), with its advantages of no pollution, small size, low power consumption and high reliability, it is setting off another revolution in lighting sources after incandescent lamps and fluorescent lamps in the history of lighting. In 1991, the advent of gallium nitride (GaN)-based blue LEDs opened up a new way to realize LED white lighting. According to the principle of three primary colors, the blue light emitted by GaN is combined with the fluorescent material that can be excited by blue light to emit yellow light, and the superposition of the two can form white light, thereby realizing white light illumination. As a result, GaN-based LEDs have developed rapidly and become the most widely used light-emit...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C04B35/10C04B35/64
Inventor 归琰杨秋红陆神州
Owner SHANGHAI UNIV
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