Preparation method for nanocrystalline alumina ceramic

A technology of nano-crystalline alumina and micro-alumina is applied in the field of low-temperature pre-sintering and high-temperature sintering to prepare nano-crystalline alumina ceramics, which can solve the problems of increasing factory production costs, difficulty in preparing nano-powders, high susceptibility to pollution, etc. The effect of reducing the cost of raw materials, optimizing the microstructure of alumina ceramics, and reducing production costs

Inactive Publication Date: 2016-09-21
SOUTHWEST JIAOTONG UNIV
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

The preparation methods of nano-ceramics mentioned above all require the use of nano-powders as raw materials. The preparation of nano-powders is relatively difficult, and due to the high activity and easy pollution, the cost of factory production is increased.

Method used

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  • Preparation method for nanocrystalline alumina ceramic
  • Preparation method for nanocrystalline alumina ceramic
  • Preparation method for nanocrystalline alumina ceramic

Examples

Experimental program
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Effect test

Embodiment 1

[0015] Example 1: Preparation of nanocrystalline alumina ceramics by low-temperature pre-firing and high-temperature sintering The specific preparation steps are as follows:

[0016] 1. Pre-pressing of ceramic powder:

[0017] Pour 2.5g of powder with a particle size of 3μm into a Φ20mm graphite mold, and mold it under a pressure of 5MPa for 60s;

[0018] 2. Sintering of ceramic powder:

[0019] Put the molded sample into a spark plasma sintering furnace, heat it to 800°C at a heating rate of 150°C / min, and keep it at this temperature for 10 minutes; 1300°C, and kept at this temperature for 2 minutes; then cooled naturally to room temperature. During the sintering process, the pressure is pre-loaded to 5kN, and then slowly increased to 50MPa during low-temperature pre-firing. The heating method is pulse current heating, the cycle pulse process is set to a single pulse time of 3.3ms, and the pause is 6.6ms after 12 consecutive pulses. Alumina ceramics with uniform nanocryst...

Embodiment 2

[0020] Embodiment 2: The preparation steps of nanocrystalline alumina ceramics are as follows:

[0021] 1. Pre-pressing of ceramic powder:

[0022] Pour 2.5g of powder with a particle size of 3μm into a Φ20mm graphite mold, and mold it under a pressure of 5MPa for 60s;

[0023] 2. Sintering of ceramic powder:

[0024] Put the molded sample into a spark plasma sintering furnace, heat it to 950°C at a heating rate of 150°C / min, and keep it at this temperature for 5 minutes; 1300°C, and kept at this temperature for 2 minutes; then cooled naturally to room temperature. During the sintering process, the pressure is pre-loaded to 5kN, and then slowly increased to 50MPa during low-temperature pre-firing. The heating method is pulse current heating, the cycle pulse process is set to a single pulse time of 3.3ms, and the pause is 6.6ms after 12 consecutive pulses. Alumina ceramics with uniform nanocrystals are finally obtained.

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Abstract

The invention discloses a preparation method for a nanocrystalline alumina ceramic. According to the preparation method, the nanocrystalline alumina ceramic is prepared from micrometer alumina powder in a discharge plasma sintering furnace through low-temperature presintering and high-temperature sintering under a discharge plasma sintering condition. The method realizes refinement of micrometer crystals through low-temperature presintering and clotting of refined crystal grain through high-temperature sintering in virtue of the special condition that the discharge plasma sintering furnace has a pulse direct-current electric field. Since the micrometer powder is used as a raw material, production cost can be greatly reduced. The method is also capable of optimizing the microscopic structure of the alumina ceramic, so the alumina ceramic has more excellent mechanical performance and thermophysical characteristics.

Description

technical field [0001] The invention relates to a method for preparing nanocrystalline alumina ceramics, which is a process for preparing nanocrystalline alumina ceramics through low-temperature pre-firing and high-temperature sintering by using a discharge plasma sintering furnace and using micron alumina powder as a raw material. Background technique [0002] Alumina ceramics have the characteristics of high mechanical strength, high hardness, excellent electrical insulation performance, etc., and are wear-resistant, high-temperature resistant, oxidation-resistant, and corrosion-resistant. Therefore, it is widely used in metallurgy, chemical industry, energy, machinery, electronics, optics, and aerospace. fields have important applications. With the development of science and technology, the requirements for material properties are becoming more and more stringent. It has become a trend to use ceramic materials to replace traditional metal materials. Therefore, the develop...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C04B35/111
CPCC04B35/111C04B2235/5436C04B2235/78
Inventor 刘金铃安立楠
Owner SOUTHWEST JIAOTONG UNIV
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