Radial-structured tubular porous ceramic and preparation method thereof

A porous ceramic and radial technology, which is applied in the field of tubular porous ceramics and its preparation, can solve the problems of difficult demoulding and unfavorable continuous production, and achieve the effects of low equipment requirements, environmental friendliness and wide application prospects

Inactive Publication Date: 2018-05-18
XI AN JIAOTONG UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

This method uses low-temperature alcohol as the freezing medium. The alcohol needs to be frozen at low temperature first, and then the alcohol is filled into the mold. During freezing, due to the heat exchange between the alcohol and the external environment and the slurry, the alcohol needs to be replaced in time to ensure Constant freezing temperature; in addition, this method uses a metal tube cavity as a mold, which makes it difficult to demould after freezing, which is not conducive to continuous production

Method used

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  • Radial-structured tubular porous ceramic and preparation method thereof
  • Radial-structured tubular porous ceramic and preparation method thereof
  • Radial-structured tubular porous ceramic and preparation method thereof

Examples

Experimental program
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Effect test

Embodiment 1

[0038] A method for preparing tubular porous ceramics with a radial structure, comprising the following steps:

[0039] (1) Using 7.5 μm SiC powder as raw material, add 0.6% dispersant sodium carboxymethyl cellulose and 5% sintering aid Al 2 o 3 , adding deionized water to prepare a ceramic slurry with a solid phase content of 20vol%, and ball milling for 30 hours;

[0040] (2) The slurry after ball milling was stirred and degassed in vacuum for 20 minutes and then poured into the cooling mold; the used cooling mold is as follows: figure 1 shown;

[0041] (3) Freeze the ceramic slurry at -40°C for about 10 minutes;

[0042] (4) Use a freeze dryer to vacuum freeze-dry the frozen green body at -55°C and 1Pa for a treatment time of 10 hours to obtain a SiC ceramic green body;

[0043] (5) Heat the green body in a resistance furnace at 600°C for 2 hours to remove organic matter, and then sinter it in an air furnace for 3 hours. The sintering temperature of the green body is 14...

Embodiment 2

[0046]A method for preparing tubular porous ceramics with a radial structure, comprising the following steps:

[0047] (1) Using 30 μm SiC powder as raw material, add dispersant sodium carboxymethyl cellulose with a mass ratio of 0.6% and sintering aid Al with a mass ratio of 5% 2 o 3 , adding deionized water to prepare a ceramic slurry with a solid phase content of 30vol%, and ball milling for 30 hours;

[0048] (2) The slurry after the ball milling was stirred and degassed in a vacuum for 20 minutes and then poured into a self-made mould;

[0049] (3) Freeze the ceramic slurry at -55°C for about 6 minutes;

[0050] (4) Use a freeze dryer to vacuum freeze-dry the frozen green body at -55°C and 1Pa for a treatment time of 5 hours to obtain a SiC ceramic green body;

[0051] (5) Heat the green body in a resistance furnace at 600°C for 2 hours to remove organic matter, and then sinter it in an air furnace for 3 hours. The sintering temperature of the green body is 1450°C to o...

Embodiment 3

[0053] A method for preparing tubular porous ceramics with a radial structure, comprising the following steps:

[0054] (1) with Si 3 N 4 powder as raw material, adding dispersant polysodium methacrylate with a mass ratio of 1%, with Y 2 o 3 and MgSiN 2 is a sintering aid, where Si 3 N 4 , Y 2 o 3 and MgSiN 2 The mol ratio is 93:1:5, then add deionized water to prepare a ceramic slurry with a solid phase content of 25vol%, and ball mill for 30 hours;

[0055] (2) The slurry after the ball milling was stirred and degassed in a vacuum for 20 minutes and then poured into a self-made mould;

[0056] (3) Freeze the ceramic slurry at -28°C for about 16 minutes;

[0057] (4) Use a freeze dryer to vacuum freeze-dry the frozen green body at -55°C and 1Pa for a treatment time of 15 hours to obtain Si 3 N 4 ceramic green body;

[0058] (5) Heat the green body in a pressure furnace at 2°C / min to 500°C, keep it for 2 hours to remove organic matter, and then heat it at 10°C / min...

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Abstract

The invention discloses radial-structured tubular porous ceramic and a preparation method thereof, and belongs to the technical field of preparation of porous ceramic materials. Water-based ceramic slurry is prepared from ceramic powder as a raw material as well as a dispersing agent and a sintering aid, ball-milling, uniform mixing and degassing are performed on the slurry, then the slurry is fedinto a cooling mold for freezing, a frozen green body is placed in a freezer dryer for sublimation of ice layers, then the dried green body is sintered, the tubular porous ceramic which is radial from inside to outside is obtained, and intervals between the ice layers decrease gradually. Meanwhile, gradient change control of pore morphology and porosity of a product can be realized by changing conditions such as slurry viscosity, raw material particle size and the like. The operation is simple, equipment requirements are low, and the tubular porous ceramic is environmentally friendly. The prepared radial-structured tubular porous ceramic has wide application prospect in purification filter, thermal insulation, bio-medical treatment, electronic devices, aerospace, energy and chemical industry and other aspects.

Description

technical field [0001] The invention belongs to the technical field of preparation of porous ceramic materials, and in particular relates to a tubular porous ceramic with a radial structure and a preparation method thereof. Background technique [0002] Porous ceramics have properties such as permeability, developed specific surface area, energy absorption, low density, and low heat conduction, and are widely used in purification and filtration, thermal insulation, biomedicine, electronic devices, aerospace, energy and chemical industries, etc. . As an environmentally friendly near-net-shape technology, freeze-drying has attracted extensive attention from scholars at home and abroad because it can be used to prepare porous materials with a unique lamellar structure. Compared with the traditional preparation process of porous ceramics, the freeze-drying method can control the shape, size and porosity of pores through the selection of slurry solid phase content, freezing temp...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C04B38/06C04B35/565C04B35/587
CPCC04B35/565C04B35/587C04B38/0605C04B2235/5436
Inventor 史忠旗杨必果张哲健夏鸿雁王继平王波王红洁杨建锋
Owner XI AN JIAOTONG UNIV
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