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A method for preparing mullite porous ceramics by welding whiskers

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

Active Publication Date: 2017-09-22
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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  • A method for preparing mullite porous ceramics by welding whiskers
  • A method for preparing mullite porous ceramics by welding whiskers
  • A method for preparing mullite porous ceramics by welding whiskers

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 demoulded samples were further frozen for 2 hours, and then transferred to a freeze dryer at 1.0 Pa, -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 demoulded samples were further frozen for 2 hours, and then transferred to a freeze dryer at 1.0 Pa, -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 ceramics, belonging to the field of porous ceramics. In the present invention, the high-temperature binder and mullite whiskers are added to the polyvinyl alcohol aqueous solution, mixed uniformly, freeze-molded in the mold, and then freeze-dried to remove moisture to obtain a flexible green body, which is placed in an air atmosphere It is sintered at 1200-1500°C to obtain a three-dimensional space network porous ceramics welded by whiskers. The porosity of porous ceramics is 50% to 90%, the pore diameter is 2 to 100 microns, and the three-point bending strength is 2 to 30 MPa. The invention is applied to the material fields of noise reduction and noise reduction, ceramic burners, molten metal filtration, gas-solid separation and the like.

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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Patent Type & Authority Patents(China)
IPC IPC(8): C04B35/185C04B35/622
Inventor 陈拥军董雷曹利华
Owner HAINAN UNIVERSITY