Mullite-whisker-reinforced anorthite porous ceramic and preparation method thereof

A technology of mullite whiskers and porous ceramics, which is applied in the field of mullite whisker-reinforced anorthite porous ceramics and its preparation, can solve problems such as low thermal conductivity, and achieves high yield, easy operation, and morphology. excellent effect

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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Inability to achieve high strength while having low thermal conductivity

Method used

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  • Mullite-whisker-reinforced anorthite porous ceramic and preparation method thereof
  • Mullite-whisker-reinforced anorthite porous ceramic and preparation method thereof
  • Mullite-whisker-reinforced anorthite porous ceramic and preparation method thereof

Examples

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Comparison scheme
Effect test

Embodiment 1

[0036] In a specific example of the preparation method of mullite whisker reinforced anorthite porous ceramics of the present invention, the raw materials used are mullite whisker powder, α-Al 2 o 3 , CaCO 3 and SiO 2 , the purity is analytically pure, the molar ratio of ingredients is 1:1:2, and the designed mullite whisker content is 50wt.%. The detailed preparation steps are as follows:

[0037] 1) Prepare the premix;

[0038]The solid content of the ceramic slurry is 25vol.%. Weigh 37.5g of deionized water into the beaker, weigh 3.75g of acrylamide powder and add it to the above beaker, weigh 0.38g of N,N'-methylenebisacrylamide and add it to the above beaker, and weigh the dispersant ammonium polyacrylate 0.19 g was placed in the above beaker. Then use JJ-1 type precision booster electric stirrer to mechanically stir to prepare the premix, the stirring speed is 2000 rpm, and the stirring time is about 30 minutes.

[0039] 2) preparing a homogeneously mixed ceramic ...

example 1

[0049] The XRD diffraction pattern of the mullite whisker reinforced anorthite porous ceramics that example 1 finally prepares is as attached image 3 As shown, the main components are mullite and anorthite, and a small amount of corundum phase exists; the typical microstructure is as attached Figure 4 As shown, mullite whiskers are attached to the pore walls of the prepared porous ceramics, and the whiskers are closely combined with the anorthite matrix. There is no agglomeration of the whiskers, and the dispersion is relatively uniform. The existence of the whiskers does not affect the formation of pores. Under high magnification, it can be found that the whiskers overlap each other, and the anorthite grains are attached to the overlaps and the surface of the whiskers; the physical properties of the prepared anorthite porous ceramics are as follows: the apparent porosity is 90.30±0.24%, Bulk density 0.278±0.008g / cm 3 , room temperature vacuum thermal conductivity 0.045±0.0...

Embodiment 2

[0051] The raw materials used are mullite whisker powder, α-Al 2 o 3 , CaCO 3 and SiO 2 , the purity is analytically pure, the molar ratio of anorthite ingredients is 1:1:2, and the designed mullite whisker content is 60mol%. The detailed preparation steps are as follows:

[0052] 1) Prepare the premix;

[0053] The solid content of the ceramic slurry is 25vol.%. Weigh 52.5g of deionized water into the beaker, weigh 5.25g of acrylamide powder and add it to the above beaker, weigh 0.53g of N,N'-methylenebisacrylamide and add it to the above beaker, and weigh the dispersant ammonium polyacrylate 0.3 g was placed in the above beaker. Then use JJ-1 type precision booster electric stirrer to mechanically stir to prepare the premix, the stirring speed is 2000 rpm, and the stirring time is about 30 minutes.

[0054] 2) preparing a homogeneously mixed ceramic slurry;

[0055] First, pour the above-mentioned uniformly mixed premix into a ball mill jar with a certain amount of a...

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Abstract

The invention provides a mullite-whisker-reinforced anorthite porous ceramic and a preparation method thereof. The preparation method comprises the following steps: preparing pure-phase high-length-diameter-ratio high-dispersibility mullite whisker by a solid reaction process, preparing a porous ceramic billet from the mullite whisker, alpha-aluminum oxide, silicon dioxide and calcium carbonate powder by a foam gelcasting process, and finally, sintering at 1450 DEG C for 5 hours to obtain the mullite-whisker-reinforced anorthite porous ceramic. The material prepared by the method has the advantages of high porosity, low thermal conductivity and high strength. The apparent porosity of the sample, in which the addition amount of the mullite whisker is 50 wt.%, is up to 90%; the room-temperature vacuum thermal conductivity is only 0.045 W/m.K; and the compression strength is up to 1.1 MPa. The research shows that the added mullite whisker inhibits the growth of the anorthite grains, and the high porosity, complicated pore structure and fine grains are main reasons for low thermal conductivity. The tight combination between the added whisker and base greatly enhances the strength of the material.

Description

technical field [0001] The invention relates to a composite porous ceramic, in particular to a mullite whisker reinforced anorthite porous ceramic and a preparation method thereof. Background technique [0002] Porous ceramics are widely used in heat insulation, catalyst support and filtration due to their low density, low thermal conductivity, high strength and excellent high temperature performance. Materials used as porous ceramic substrates mainly include corundum, mullite, cordierite, zirconia, anorthite and silicon carbide. Among them, anorthite has a higher melting point (1550°C), lower density (2.74-2.76g / cm 3 ), lower coefficient of thermal expansion (4.82×10 -6 K -1 ) and low thermal conductivity (3.67W / (m K)), which are considered as excellent candidates for thermal insulation. But the lower service temperature (1260°C) and lower strength limit its application. [0003] Mullite has high strength and low thermal conductivity. At the same time, the melting poin...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C04B38/00C04B35/81
Inventor 李翠伟韩耀边超杨菁
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