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Preparation method of mullite porous ceramic by welding whisker

A technology of porous ceramics and mullite, applied in the field of porous ceramics, can solve the problems of high whisker density, easy deposition, difficult whisker dispersion, etc., and achieve good application prospects, good strength and toughness

Active Publication Date: 2015-12-02
HAINAN UNIVERSITY
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The effect of mullite whisker toughening ceramics is remarkable, but whiskers are difficult to disperse in the solid phase and are easy to grind. In water, the dispersion of whiskers has always been a problem due to the high density of whiskers and easy deposition.

Method used

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  • Preparation method of mullite porous ceramic by welding whisker
  • Preparation method of mullite porous ceramic by welding whisker
  • Preparation method of mullite porous ceramic by welding whisker

Examples

Experimental program
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Effect test

Embodiment 1

[0023] Add 23.6g mullite whiskers and 0.29g lanthanum oxide to 20ml, 5wt% PVA aqueous solution, stir the obtained mixture under a magnetic stirrer at room temperature for 10min, then ultrasonically disperse at room temperature for 3min, boil and concentrate to 10ml A ceramic slurry is obtained. 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 in a low temperature environment of -18°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 at 10°C / min to 800°C in an air atmosphere, kept at 1h, and then heated at 7°C / min to 1450°C for 2h for sintering. The obtained mullite porous ceramics are as attached figure 2 ;

Embodiment 2

[0025] Add 6g mullite whiskers and 0.16g nano-silicon dioxide to 20ml, 5wt% PVA aqueous solution, stir the obtained mixture uniformly under a magnetic stirrer at room temperature for 5min, then ultrasonically disperse at room temperature for 3min, and let it stand for 24h A ceramic slurry is obtained. 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 in a low temperature environment of -18°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 up to 800°C at 10°C / min in an air atmosphere, kept at 1h, then raised to 1450°C at 7°C / min for 2h, and then sintered. The obtained mullite porous ceramics are as attached image 3 .

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Abstract

The invention relates to a preparation method of mullite porous ceramic, and belongs to the field of porous ceramics. A high temperature binder and mullite whiskers are added into an aqueous solution of polyvinyl alcohol, and the solution is uniformly mixed and is refrigerated and molded in a die; freeze drying is carried out for removing moisture, and then a flexible base substrate is obtained; the base substrate is placed in air atmosphere and is sintered at 1200-1500 DEG C, and then a three-dimension network shaped porous ceramic is obtained by whisker welding. The porosity of the porous ceramic is 50-90%, the aperture is 2-100 micrometer, and the three point bending strength is 2-30MPa. The method is applied in the fields of noise reduction, ceramic combustor, molten metal filtering and gas-solid separation and other materials.

Description

technical field [0001] The invention relates to a method for preparing mullite porous ceramics by a whisker welding process, that is, a method for preparing mullite porous ceramics by welding mullite whiskers with rare earth oxides or nano silicon dioxide, and 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, Materials fields such as molten metal filtration and gas-solid separation 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. CN103833400) used alumina and sili...

Claims

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Application Information

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IPC IPC(8): C04B35/185C04B35/622
Inventor 陈拥军董雷曹利华
Owner HAINAN UNIVERSITY