Preparation method of acicular mullite porous ceramic block material with superhigh amount of porosity

A technology of acicular mullite and porous ceramics, applied in the field of porous ceramics, can solve the problems of no room for whiskers to grow, difficult to disperse whiskers, and difficult to grow in situ, etc., to achieve good strength and toughness

Inactive Publication Date: 2015-11-25
HAINAN UNIVERSITY
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0003] In terms of structural ceramics, it is a common method to toughen ceramics by adding whiskers, and the effect is remarkable, but the whiskers are diffi

Method used

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  • Preparation method of acicular mullite porous ceramic block material with superhigh amount of porosity
  • Preparation method of acicular mullite porous ceramic block material with superhigh amount of porosity
  • Preparation method of acicular mullite porous ceramic block material with superhigh amount of porosity

Examples

Experimental program
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Effect test

Embodiment 1

[0024] Add ceramic powder with a solid content of 50% (volume fraction) to 50ml of an aqueous solution containing 10wt% PVA, wherein the mass ratio of aluminum hydroxide, silicon dioxide, aluminum fluoride and vanadium pentoxide is 77:20:1.5 :1.5. The obtained mixture was stirred with a magnetic stirrer at room temperature for 10 min, and then ultrasonically dispersed at room temperature for 3 min, then boiled and concentrated to 10 ml to obtain a ceramic slurry. Pour the ceramic slurry into a cylindrical mold in batches (the bottom of the mold is made of pure copper, and the wall is made of polytetrafluoroethylene), and then refrigerated at -18°C for 10 minutes before demoulding. The demolded samples were further frozen for 1 hour, and then transferred to a freeze dryer at 1.0 Pa and freeze-dried at -50°C for 24 hours to remove moisture. The ceramic green body after dehydration was moved to a high-temperature tubular electric furnace, heated to 300°C at a rate of 10°C / min in...

Embodiment 2

[0026] Add ceramic powder with a solid content of 50% (volume fraction) to 50ml of an aqueous solution containing 7wt%PVA, wherein the mass ratio of aluminum hydroxide, silicon dioxide, aluminum fluoride and vanadium pentoxide is 76:19:3 :2. The obtained mixture was stirred with a magnetic stirrer at room temperature for 5 minutes, then ultrasonically dispersed at room temperature for 3 minutes, and then left to stand for 24 hours to obtain a ceramic slurry. Pour the ceramic slurry into a cylindrical mold in batches (the bottom of the mold is made of pure copper, and the wall is made of polytetrafluoroethylene), and then freeze at -60°C for 10 minutes before demoulding. The demolded samples were further frozen for 2 hours, and then transferred to a freeze dryer at 1.0 Pa, and freeze-dried at -50°C for 24 hours to remove moisture. The dehydrated ceramic green body was moved to a tube furnace, heated to 800°C at a rate of 5°C / min in an air atmosphere, kept for 2 hours, and then...

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Abstract

The present invention discloses a preparation method of mullite porous ceramic with cluster-like whisker structure. The method is as below: dispersing aluminum hydroxide, silica, aluminum fluoride and vanadium pentoxide powder in a polyvinyl alcohol (PVA) aqueous solution; mixing evenly and freezing in a mold; separating PVA and water; crosslinking a PVA molecular chain, and curing the ceramic powder by the PVA molecular chain and ice; and then freeze-drying, batching and sintering to obtain the mullite porous ceramic with in-situ grown whiskers, porosity of 50%-90%, and compressive strength of 2-15 MPa. The present invention can be applied to the fields of muffler noise reduction, catalyst carrier and gas-solid separation.

Description

technical field [0001] The invention relates to a method for preparing an ultra-high porosity acicular mullite porous ceramic block material, which uses a PVA-based cryogel injection molding process combined with a mullite whisker in-situ growth technology to prepare mullite porous ceramics , belongs to the field of porous ceramics. Background technique [0002] Due to its low thermal conductivity and thermal expansion coefficient, high creep resistance and thermal shock stability, excellent electrical insulation, chemical stability and high temperature strength, mullite porous ceramics are used in noise reduction, ceramic burners, Fields such as molten metal filtration and gas-solid separation materials show broad application prospects. Jiang Dongliang et al. (Chinese Patent, Patent Publication No. CN101037345) used silica and alumina as the main raw materials to prepare mullite porous ceramics by gel freeze-drying. Yuan Lei et al. (Chinese Patent, Patent Publication No. ...

Claims

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Application Information

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IPC IPC(8): C04B35/185C04B38/06
Inventor 陈拥军董雷骆丽杰曹利华李建保李豪
Owner HAINAN UNIVERSITY
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