Method for preparing gradient porous ceramic by using centrifugal freeze drying technology

A gradient porous and ceramic technology, applied in ceramic products, applications, household appliances, etc., can solve problems such as material failure, achieve good mechanical properties and stability, and small residual stress

Active Publication Date: 2014-07-02
XIAN UNIV OF TECH
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  • Abstract
  • Description
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  • Application Information

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Problems solved by technology

[0007] The purpose of the present invention is to provide a method for preparing gradient porous ceramics by centrifugal freeze-drying technology, which solves the problem that the interface of porous ceramics with gradient changes in porosity changes abruptly or changes in steps to form residual stress and cause material failure.

Method used

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  • Method for preparing gradient porous ceramic by using centrifugal freeze drying technology
  • Method for preparing gradient porous ceramic by using centrifugal freeze drying technology

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Embodiment 1

[0040] 20ml Al 2 o 3 Add the powder into 80ml of distilled water and mix evenly to obtain a volume concentration of 20% Al 2 o 3 Suspension; take 90g Al 2 o 3 Suspension, add 7g sodium polyacrylate and 3g polyvinyl alcohol into Al 2 o 3 In the suspension, mix evenly to obtain Al 2 o 3 slurry; Al 2 o 3The slurry is injected into a cylindrical mold with a heat transfer material on the bottom surface and an insulating material on the side, and then the mold injected with the slurry is centrifuged at 3500rpm for 12h on a centrifuge, and then the bottom of the mold is immersed in a methanol liquid cold source at -60°C and cooled. Maintain centrifugal rotation; Al 2 o 3 After the slurry was completely frozen, it was taken out and placed in an environment with a pressure of 200Pa to dry under low pressure to obtain a gradient porous Al 2 o 3 ceramic preform; the gradient porous Al 2 o 3 Ceramic preforms are sintered at a temperature of 1700°C to produce Al 2 o 3 Grad...

Embodiment 2

[0042] Add 30ml of hydroxyapatite powder into 70ml of distilled water, and mix evenly to obtain a hydroxyapatite suspension with a volume concentration of 30%; take 88g of hydroxyapatite suspension, mix 8g of sodium polyacrylate and 4g of carboxymethyl The cellulose is added to the hydroxyapatite ceramic suspension, and mixed evenly to obtain a hydroxyapatite ceramic slurry; the hydroxyapatite slurry is injected into a cylindrical mold with a heat transfer material on the bottom surface and an insulating material on the side, and then Centrifuge the mold injected with the slurry at 2000rpm for 4 hours on a centrifuge, then immerse the bottom of the mold in a liquid cold source of ethanol at -30°C and maintain the centrifugal rotation; after the hydroxyapatite slurry is completely frozen, take it out and place it under a pressure of The gradient porous hydroxyapatite ceramic preform is obtained by drying under low pressure in an environment of 0 Pa; the gradient porous hydroxyap...

Embodiment 3

[0044] 10ml TiO 2 Add the powder into 90ml distilled water and mix evenly to obtain TiO with a volume concentration of 10%. 2 Suspension; by mass percentage, take 93g TiO 2 Suspension, add 5g sodium dodecylbenzenesulfonate and 2g carboxymethyl cellulose to TiO 2 In the suspension, mix evenly to get TiO 2 slurry; the TiO 2 The slurry is injected into a cylindrical mold with a heat transfer material on the bottom and an insulating material on the side, and then the mold injected with the slurry is centrifuged at 500 rpm for 1 hour, and then the bottom of the mold is immersed in a mixture of liquid nitrogen and ethanol at -90°C In a cold source and kept in centrifugal rotation; TiO 2 After the slurry is completely frozen, take it out, place it in an environment with a pressure of 400Pa and dry it under low pressure to obtain a gradient porous TiO 2 ceramic preform; the gradient porous TiO 2 The ceramic preform is sintered at a temperature of 1300°C to obtain TiO 2 Gradient...

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Abstract

The invention discloses a method for preparing a gradient porous ceramic by using centrifugal freeze drying technology. The method comprises the following steps: firstly, preparing ceramic slurry by using ceramic powder, distilled water, a dispersing agent and an adhesive, injecting the ceramic slurry into a mold, centrifugally rotating, directionally freezing, drying under low pressure and sintering to obtain a porous ceramic of which the porosity shows continuous gradient change. The gradient porous ceramic prepared by the method is of an 'inner sparse, outer dense' bionic structure; the porosity shows continuous gradient change from inside to outside; the gradient porous ceramic has small residue stress, good mechanical property and good stability, can be widely applied to fields such as filtering materials, catalyzer carriers, vibration-absorptive materials, fuel cells, artificial bone substitute materials and drug release carriers.

Description

technical field [0001] The invention belongs to the technical field of material preparation, and in particular relates to a method for preparing gradient porous ceramics by centrifugal freeze-drying technology. Background technique [0002] Porous ceramic materials are widely used in filtration, penetration, heat insulation, sound absorption, adsorption, reaction sensing, etc. due to their advantages of high porosity, large specific surface area, low density, low thermal conductivity, high temperature resistance, and corrosion resistance. field. In the preparation methods of porous ceramic materials, such as adding pore-forming agent method, chemical foaming method, template replication method and sol-gel method, although the prepared porous ceramics can obtain better functionality, their strength is due to the The increase of porosity decreases sharply, so how to improve the strength of porous ceramics is the focus of current research. [0003] A large number of studies h...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C04B38/06C04B35/622
Inventor 赵康汤玉斐胡龙徐雷
Owner XIAN UNIV OF TECH
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