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Method for preparing in-situ self-toughening alumina ceramics

A self-toughening technology for alumina ceramics, applied in the field of preparation of in-situ self-toughened alumina ceramics, can solve the problem of high cost and achieve simple and controllable equipment and processes

Inactive Publication Date: 2010-06-02
TSINGHUA UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

The equipment and process are simple and controllable. The prepared ceramic products are composed of alumina containing long columnar and plate-like crystals, which solves the difficulties caused by the use of fibers and whiskers and carbon nanotubes in traditional processes (such as dispersion and high cost), as well as some defects in ceramic products caused by the introduction of additives, provide a new idea for the toughening of alumina ceramics

Method used

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  • Method for preparing in-situ self-toughening alumina ceramics
  • Method for preparing in-situ self-toughening alumina ceramics
  • Method for preparing in-situ self-toughening alumina ceramics

Examples

Experimental program
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Effect test

Embodiment 1

[0025] Weigh the initial raw material 40g Al 2 o 3 and 0.004g Al powder into a nylon resin ball mill jar, use alumina balls with a purity of 99%, add polyethylene glycol with a mass fraction of alumina powder of 1‰ and 250mL alcohol, and perform wet ball milling in a high-energy ball mill for 8 hours . Put the mixture after high-energy ball milling into a 99% alumina ceramic crucible, dry it in an oven at 50°C to obtain a uniformly mixed powder, shape it with various molding methods, and sinter it at 1550°C in an ordinary sintering furnace under an air atmosphere. Hours, a single-phase alumina ceramic with in-situ growth of long columnar and plate-like crystals is obtained, and its typical structure is as follows figure 1 shown. Depend on figure 1 It can be seen that the prepared alumina ceramic grains have appeared tabular crystals or long columnar crystals with an aspect ratio greater than 2.

Embodiment 2

[0027] Weigh the initial raw material 40g Al 2 o 3 and 0.02g Al powder into a nylon resin ball mill jar, use alumina grinding balls with a purity of 99%, add polyethylene glycol with a mass fraction of alumina powder of 5‰ and 250mL alcohol, and perform wet ball milling in a high-energy ball mill for 10 hours . Put the mixture after high-energy ball milling into a 99% alumina ceramic crucible, and dry it in an oven at 50°C to obtain a uniformly mixed powder, which is formed by cold isostatic pressing and sintered at 1580°C in an ordinary sintering furnace under an air atmosphere. Hours, a single-phase alumina ceramic with in-situ growth of long columnar and plate-like crystals is obtained, and its typical structure is as follows figure 2 shown. Depend on figure 2 It can be seen that there are long columnar and plate-like crystals with a large area as shown by the arrows, and these abnormally grown grains form a certain degree of interpenetrating network structure, the lo...

Embodiment 3

[0029] Weigh the initial raw material 40g Al 2 o 3 and 0.04g Al powder into a nylon resin ball mill jar, use alumina grinding balls with a purity of 99%, add polyethylene glycol with a mass fraction of alumina powder 1% and 250mL alcohol, and perform wet ball milling in a high-energy ball mill for 12 hours . Put the mixture after high-energy ball milling into a 99 alumina ceramic crucible, dry it in an oven at 50°C to obtain a uniformly mixed powder, shape it by injection molding, and sinter at 1560°C for 3 hours in an ordinary sintering furnace under an air atmosphere , to obtain single-phase alumina ceramics with in-situ growth of long columnar and plate-like crystals, and its typical structure is as follows image 3 shown. Depend on image 3 It can be seen that a large area of ​​long columnar and plate-like crystals appears, as shown by the arrows, these irregularly grown grains form a certain degree of interpenetrating network structure, the longest grain aspect ratio ...

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Abstract

A preparation method of an in-situ self-toughening alumina ceramic includes the following specific steps of the process: uniformly mixing initial raw materials of nano-aluminum and alumina with high purity; drying and grinding the mixed slurry into powders; forming the obtained powders into a green body; sintering the green body directly in a common air sintering oven to obtain ceramic material. The method is characterized in that: alumina ceramics which are equipped with in-situ growth long columnar and platelet grains can be produced; the process is hopeful to both reserve obvious tougheningand reinforcement effects of traditional fibers and whiskers and directly solve the difficulties brought by the fibers, the whiskers and carbon nano-tubes on the using process. Amorphous promoters ofSiO2, TiO2, La2O3, CAS (CaO-Al2O3-SiO2, etc. are not needed to be added. A final aluminum oxide product only contains single alumina phase and has the advantages of high density, high purity and hightoughness.

Description

technical field [0001] The invention relates to the technical field of preparation of ceramic materials, and in particular provides a preparation method of in-situ self-toughening alumina ceramics. Background technique [0002] Alumina ceramic materials have excellent mechanical and electrical properties, and low manufacturing cost, and are currently the most widely used advanced ceramic materials. Alumina precision ceramic materials with a bending strength of 700-1000Mpa can be prepared by using high-purity submicron alumina ultrafine powder. However, the fracture toughness of this material is very low, usually only 3-4Mpa·m1 / 2. Therefore, improving the fracture toughness of alumina ceramics has always been the goal that ceramic material workers expect and strive for. [0003] There are generally four methods for ceramic toughening: dispersion toughening, phase transformation toughening, fiber and whisker toughening, and the recently developed carbon nanotube toughening. ...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C04B35/10C04B35/622
Inventor 谢志鹏张新霓黄勇
Owner TSINGHUA UNIV
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