Method for preparing closed-pore porous heat-insulating alumina ceramic

A porous alumina and closed-cell technology, which is applied in ceramic products, applications, household appliances, etc., can solve the problems of excessive additives, easy pulverization of products, complex porous ceramic process, etc., and achieve simple process and excellent heat insulation performance Effect

Active Publication Date: 2015-03-25
NORTHWESTERN POLYTECHNICAL UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0008] In order to avoid the deficiencies of the prior art, the present invention proposes a method for preparing closed-cell porous alumina heat-insulating ceramics, wh

Method used

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  • Method for preparing closed-pore porous heat-insulating alumina ceramic
  • Method for preparing closed-pore porous heat-insulating alumina ceramic
  • Method for preparing closed-pore porous heat-insulating alumina ceramic

Examples

Experimental program
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Effect test

Embodiment 1

[0029] (1) 4g of Al(NO 3 ) 3 9H 2 O and 10 g of glucose were dissolved in 140 mL of deionized water, stirred to a colorless and transparent solution, and placed in a 200 mL hydrothermal reaction kettle.

[0030] (2) Put the three sets of sealed hydrothermal reaction kettles in a blast drying oven, raise the temperature to 160°C, hold the heat for 16h, 20h and 24h respectively, and cool down to room temperature naturally after the reaction.

[0031] (3) Open the hydrothermal reaction kettle, the product is collected by suction filtration, and then washed several times with deionized water and absolute ethanol; the collected precipitate is dried in a drying oven at 60°C, and the black precipitate is placed in a muffle furnace for 900 ℃ heat treatment for 2h (argon atmosphere), to obtain the precursor A. The shape of the precursor is as figure 2 shown.

[0032] (4) Al 2 o 3 The Al 2 o 3 Slurry B.

[0033] (5) Place precursor A in slurry B (mass ratio A:B=1:99), mechani...

Embodiment 2

[0037] (1) 3g of Al 2 (SO 4 ) 3 18H 2 O and 5g of glucose were dissolved in 80mL of deionized water, stirred to a colorless and transparent solution, and placed in a 100mL hydrothermal reaction kettle.

[0038] (2) Put the three sets of sealed hydrothermal reaction kettles in a blast drying oven, raise the temperature to 180°C, hold the heat for 16h, 20h and 24h respectively, and cool down to room temperature naturally after the reaction.

[0039] (3) Open the hydrothermal reaction kettle, collect the product by suction filtration, and then wash several times with deionized water and absolute ethanol; dry the collected product in a drying oven at 60°C to obtain precursor A.

[0040] (4) Al 2 o 3 Powder, MgO and TiO 2 Mix in absolute ethanol at a mass ratio of 95:4:1 and place it in a planetary ball mill for 10 hours to prepare Al 2 o 3 Slurry B.

[0041] (5) Place precursor A in slurry B (mass ratio A:B=1:99), mechanically stir for 5 hours after ultrasonication for 30 m...

Embodiment 3

[0044] (1) 2g of Al(NO 3 ) 3 9H 2 O and 5g of glucose were dissolved in 60mL of deionized water, stirred to a colorless and transparent solution, and placed in a 100mL hydrothermal reaction kettle.

[0045] (2) Place the sealed hydrothermal reaction kettle in a blast drying oven, heat up to 160° C., keep it warm for 24 hours, and cool down to room temperature naturally after the reaction.

[0046] (3) Open the hydrothermal reaction kettle, the product is collected by suction filtration, and then washed several times with deionized water and absolute ethanol; the collected product is dried in a drying oven at 60°C to obtain a black precipitate; the black precipitate is placed in a muffle Precursor A was obtained by heat treatment at 1200° C. for 2 hours in a furnace (argon atmosphere).

[0047] (4) Al 2 o 3 Powder, MgO and TiO 2 Mix in absolute ethanol at a mass ratio of 90:9:1 and place it in a planetary ball mill for 10 hours to prepare Al 2 o 3 Slurry B.

[0048] (5...

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Abstract

The invention relates to a method for preparing a closed-pore porous heat-insulating alumina ceramic. According to the method, a powder which is prepared by adopting a hydrothermal synthesis method and is in a core-shell structure is added into alumina slurry as a pore forming agent to prepare an alumina ceramic, in the process of sintering an alumina ceramic blank, the carbon sphere as a core is removed under oxidization, the alumina layer as a shell and the alumina substrate are sintered compactly to form a magnesium-aluminium spinel together with a sintering additive, and the magnesium-aluminium spinel is pined into the grain boundary. Closed pores are introduced into the prepared alumina ceramic successfully, the rate of closed pores of the alumina ceramic is up to10-60%, and the rate of open pores is less than 5%. The thermal conductivity of the alumina ceramic is 0.1W/(m.K), and the usage temperature is over 1,400 DEG C. The method provided by the invention can be used for overcoming the defects that the existing process for preparing the porous ceramic by foaming is complex, too many additives are added, and the product is easy to powderize.

Description

technical field [0001] The invention belongs to a method for preparing porous ceramics, and relates to a method for preparing closed-cell porous alumina heat-insulating ceramics. Background technique [0002] Heat insulation materials are widely used in linings and insulation layers of kilns and high-temperature equipment. Lightweight, high-strength, high-temperature-resistant heat-insulating ceramics are the focus of current development. Among the existing heat insulation materials of various materials, there are zirconia, silicon, magnesium, high alumina, etc. according to the raw materials. Among them, there are the most types of alumina heat insulation materials, such as alumina fiber, high alumina Insulation bricks, alumina hollow ball products, etc. Compared with ordinary heat insulation materials, alumina heat insulation materials have the characteristics of low bulk density, high load softening temperature, high compressive strength, low heat capacity, etc., and are...

Claims

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Application Information

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IPC IPC(8): C04B38/06C04B35/10C04B35/622
Inventor 殷小玮韩美康成来飞任飒
Owner NORTHWESTERN POLYTECHNICAL UNIV
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