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Method for producing porous ceramic with oriented structure by employing freeze dehydration

A freeze-drying method, a technology of porous ceramics, applied in the field of preparing directional porous ceramic materials, can solve the problems of environmental pollution, limited materials suitable for the process, difficult to control the pore structure, etc., achieve small sintering shrinkage, realize net size molding, and less organic additives. Effect

Inactive Publication Date: 2009-05-13
BEIHANG UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

At present, the preparation techniques of porous materials include organic foam impregnation method, adding pore-forming agent method, extrusion molding process, sol-gel process, etc., but these methods have certain limitations, such as organic matter is easy to cause environmental pollution, and the application of the process Materials are limited, pore structure is difficult to control, etc.

Method used

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  • Method for producing porous ceramic with oriented structure by employing freeze dehydration
  • Method for producing porous ceramic with oriented structure by employing freeze dehydration
  • Method for producing porous ceramic with oriented structure by employing freeze dehydration

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0019] Preparation of α-Al with Oriented Structure by Freeze-drying 2 o 3 porous ceramic material.

[0020] The raw material used is α-alumina (α-Al 2 o 3 ), the dispersant is ammonium polyacrylate (NH 4 PAA), binder is polyvinyl alcohol (PVA).

[0021] Add 100g of α-Al to the ball mill jar 2 o 3 , 1g of NH 4 PAA, 30.5ml of deionized water, ball milled for 0.5 hours to prepare a slurry; add 5ml of PVA solution to the slurry and adjust the pH to 8.5, mix evenly and inject into the mold, and put it into the freezing medium at -20°C to freeze Freeze in the device for 0.5 hours, take it out, and place it in a vacuum box for 5 hours to obtain the biscuit; put the biscuit into a high-temperature furnace at 1300 ° C, sinter for 1 hour, and cool to room temperature with the furnace temperature to obtain a oriented structure. α-Al 2 o 3 porous ceramic material.

[0022] Determination of α-Al with Oriented Structure by Archimedes Drainage Method 2 o 3 The porosity of the po...

Embodiment 2

[0027] Preparation of α-Al with Oriented Structure by Freeze-drying 2 o 3 porous ceramic material.

[0028] Add 100g of α-Al to the ball mill jar 2 o 3 , 0.5g of NH 4 PAA, 100ml of deionized water, ball milled for 0.5 hours to prepare a slurry; add 5ml of PVA solution to the slurry and adjust the pH to 8.5, mix evenly and inject into the mold, and put the freezing medium temperature into a freezer at -20°C Freeze for 0.5 hours, take it out, and place it in a vacuum box for 5 hours to get the biscuit; put the biscuit in a high-temperature furnace at 1300 ° C, sinter for 1 hour, and cool to room temperature with the furnace temperature to obtain α -Al 2 o 3 porous ceramic material.

[0029] Determination of α-Al with Oriented Structure by Archimedes Drainage Method 2 o 3 The porosity of the porous ceramic material is 75.7%.

[0030] Testing α-Al with Oriented Structure by Material Mechanics Tester 2 o 3 The compressive strength of the porous ceramic material is 0.3MP...

Embodiment 3

[0032] Add 100g of α-Al to the ball mill jar 2 o 3 , 5g of NH 4 PAA, 37.5ml of deionized water, after ball milling for 0.5 hours, prepare a slurry; add 5ml of PVA solution to the slurry and adjust the pH to 8.5, mix evenly and inject into the mold, put into the freezing medium temperature -20 ℃ freezing device Freeze for 0.5 hours, take it out, and place it in a vacuum box for 5 hours to get the biscuit; put the biscuit into a high-temperature furnace at 1550 ° C, sinter for 1 hour, and cool to room temperature with the furnace temperature to obtain α with oriented structure. -Al 2 o 3 porous ceramic material.

[0033] Determination of α-Al with Oriented Structure by Archimedes Drainage Method 2 o 3 The porosity of the porous ceramic material is 40.1%.

[0034] Testing α-Al with Oriented Structure by Material Mechanics Tester 2 o 3 The compressive strength of the porous ceramic material is 160.9MPa.

[0035] α-Al with oriented structure prepared by mercury intrusion ...

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Abstract

The invention discloses a method for preparing porous ceramics with a directive structure by a freeze drying method, which is a forming method for directly obtaining the porous ceramics by using congelation of ceramic slurry and decompression, drying and removal of impurities. Compared with other porous preparation technologies, the method is a method capable of preparing porous materials with high directing property, high porosity and complex shape, does not add a large quantity of organic pore forming materials, and is an environment-friendly technology. The main characteristic of the method is to control a porous structure by using the action of the medium solidifying process on ceramic particles. The porous ceramic materials are prepared by adding 0.5 to 5 grams of ammonium polyacrylate, 20 to 100 milliliters of deionized water and 0.5 to 5 milliliters of polyvinyl alcohol into 100 grams of alpha-alumina.

Description

technical field [0001] The invention relates to a method for making porous ceramic materials, more particularly, refers to a method for preparing oriented porous ceramic materials by adopting a freeze-drying method. The prepared oriented porous ceramic material has a porous structure and is composed of macroscopically oriented channels parallel to the freezing temperature gradient direction and micropores distributed on the pore walls. Background technique [0002] The continuous improvement of the gas temperature before the turbine of the aero-engine requires the improvement of the blade cooling efficiency, and the key of this technology lies in the manufacture of the ceramic core. At present, the existing high-efficiency air-cooled blade ceramic cores are mainly divided into two types: silica-based and alumina-based. Compared with silica-based ceramic cores, alumina ceramic cores have better metallurgical chemical stability and creep resistance, which can ensure the dimen...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C04B38/00C04B35/00C04B35/622
Inventor 张跃邹景良唐晓霞
Owner BEIHANG UNIV
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