Alumina ceramic and preparation method thereof

A technology of alumina ceramics and alumina, which is applied in the field of ceramic materials, can solve the problems of easy aggregation and difficult dispersion of raw material particle size, achieve the effect of widening the particle size range, improving sintering efficiency, and avoiding the process of debinding

Active Publication Date: 2008-02-06
BEIJING SINOMA SYNTHETIC CRYSTALS CO LTD +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

This application has not yet addressed the use of ultrafine particulate Al 2 o 3 The particle size of the raw material is easy to agglomerate and difficult to disperse during use, and it must go through a debinding process for several hours before sintering

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0041] Embodiment 1: Preparation of 99.5% alumina ceramic substrate by cold isostatic pressing

[0042] The formula composition of this product is (calculated by mass percentage): the purity of alumina raw material is more than 99%.

[0043] α-Al 2 o 3 : 59.5%, γ-Al 2 o 3 : 40%; MgO: 0.2%, Y 2 o 3 : 0.2%; Tm 2 o 3 : 0.1%, which adds up to 100%.

[0044] Put the weighed alumina powder into the ball mill according to the formula requirements, wherein MgO, Y 2 o 3 、Tm 2 o 3 Introduced in the form of nitrate, with 50% alcohol as the medium, adding 1‰ ammonium polyacrylate as dispersant, 3‰ stearic acid as ball milling aid, and ball milling for 72 hours into slurry. Dissolve and disperse in a water bath at 80°C before adding stearic acid. The uniformly mixed slurry is passed through a 300-mesh material sieve and placed in an oven to dry at 90°C. The dried powder is calcined at 800°C for 3 hours to decompose magnesium nitrate, yttrium nitrate, and thulium nitrate into ...

Embodiment 2

[0046] Embodiment 2: Preparation of 99.6% alumina ceramic crucible by grouting method

[0047] The formula composition of this product is (calculated by percentage composition):

[0048] α-Al 2 o 3 : 89.6%, γ-Al 2 o 3 : 10%; MgO: 0.2%, yttrium-stabilized zirconia: 0.2%, and the total is 100%.

[0049] Put the weighed alumina powder into the ball mill according to the formula requirements, wherein MgO is introduced in the form of its nitrate, and the water with a total percentage of 30% is used as the medium, and 1‰ ammonium polyacrylate is added as a dispersant The mixture of sodium hexametaphosphate and sodium hexametaphosphate is used as a dispersant, 3‰ stearic acid is used as a ball milling aid, and the slurry is made by ball milling for 72 hours. The viscosity of the slurry is 1000-1500mPa·s. The evenly mixed slurry is directly injected into the gypsum mold, solidified, and demolded after emptying the slurry, and the green body is dried in an oven at 60°C, and the fr...

Embodiment 3

[0050] Example 3: Preparation of 99.9% alumina ceramic grinding balls by cold isostatic pressing

[0051] The formula composition of this product is (calculated by mass percentage composition):

[0052] The purity is 99.99% α-Al 2 o 3 : 74.5%, γ-Al 2 o 3 : 25.4%; MgO: 0.1%. Its concrete mixing, granulation, product sintering steps are the same as embodiment 1. The granulation powder is directly added into the mold for 110MPa cold isostatic pressing, and the formed green ball is trimmed and then dried at 80°C to remove the adsorbed water in the green body.

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Abstract

The invention provides alumina ceramics and a manufacturing method of the alumina ceramics. The main materials of the alumina ceramics are as follows: alumina micro mist or a superfine alumina micro mist which is formed by Gamma alumina and an Alpha alumina with an particle diameter of between zero point one to three point five micron and a purity of ninety-nine point nine percent or more than ninety-nine point nine percent according to certain proportion. One or a mixture of a small quantity of magnesia, yttria, lanthana, thulia and yttria stabilized zirconia is added into the micro mist as sinter accessory ingredient and is subject to dry pressing, grouting and isostatic cool pressing after being even mixed evenly, thus ceram green pressing is obtained. Only a little organic addition agent is needed to be added. After drying, the green pressing body does not need to be roasted and can be directly introduced to an ordinary high temperature si-mo rod resistance furnace or a continuous type si-mo rod electrothermal tunnel kiln to be sintered for one to three hours at a temperature below one thousand six hundred and seventy Celsius system. Therefore, the alumina ceramics can be obtained with high tightness, mechanical property and good dielectric property and with a nonconventional structure and a placode the size of which is zero point two to two hundred millimeter and a purity of ninety nine to ninety-nine point nine percent.

Description

technical field [0001] The invention relates to the field of ceramic materials, in particular to ceramics with an alumina content as high as 99-99.9 percent and sintered at a low temperature of 1670° C., and relates to an alumina ceramic and a preparation method thereof. Background technique [0002] As a high-temperature structural material, alumina ceramics have been widely used in various fields, but usually alumina ceramic products are more and more difficult to sinter with the increase of alumina content. The continuous electrothermal tunnel kiln (limit temperature lower than 1700°C) in general industrial production will be difficult to sinter high-density alumina products with more than 99%. Therefore, it is necessary to use a batch-type hydrogen atmosphere furnace or a hot-pressed sintering furnace for sintering. These two methods have higher requirements on equipment, higher production costs and limited output. [0003] With the development of technology, at presen...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C04B35/111C04B35/622
Inventor 孙峰张伟儒田庭燕武七德王培陈波朱新华
Owner BEIJING SINOMA SYNTHETIC CRYSTALS CO LTD
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