Preparation method of self-reinforced mullite porous ceramic

A technology of porous ceramics and mullite, which is applied in the field of porous ceramic materials, can solve the problems of low mullite content and low strength, and achieve the effect of improving performance, high strength and high fiber content

Inactive Publication Date: 2014-06-04
NORTHEASTERN UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0004] The purpose of the present invention is to provide a preparation method of low raw material cost, simple production process, high-strength fiber self-reinforced mullite porous ceramics containing a large amount of acicular structure mullite in the porous ceramics, which overcomes the current in-situ synthesis of porous ceramics. The mullite content of needle-like structure in the mullite matrix is ​​less, and the strength is lower

Method used

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  • Preparation method of self-reinforced mullite porous ceramic
  • Preparation method of self-reinforced mullite porous ceramic

Examples

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Embodiment 1

[0012] 38.4% by mass of kaolin, 31.6% of industrial alumina powder, and 30% of starch are used as raw materials for batching, and 15% of ammonium fluoride is added as an additive, mixed and ball milled for 24 hours, and formed under a pressure of 30MPa. The molded green body is kept at a temperature of 1500° C. for 2 hours to obtain fiber self-reinforced mullite porous ceramics.

[0013] The product prepared by the method of this embodiment has an apparent porosity of 51%, and a bulk density of 1.53 g / cm 3 , The three-point flexural strength is 48.6MPa. figure 1 and figure 2 From this example, figure 1 It shows that the prepared porous ceramic crystal phase is mullite phase, figure 2 It shows that there are a large number of mullite fibers with acicular structure in porous ceramics.

Embodiment 2

[0015] The mass percentage is 39.6% of Guangxi white mud, 40.4% of industrial alumina powder, 20% of starch as raw materials, and 15% of ammonium fluoride is added as an additive, mixed and ball milled for 24 hours, under a pressure of 30MPa forming. The molded green body is kept at a temperature of 1600° C. for 2 hours to obtain fiber self-reinforced mullite porous ceramics.

[0016] The product prepared by the method of this embodiment has an apparent porosity of 36% and a bulk density of 1.85 g / cm 3 , the three-point flexural strength is 85.4MPa, and there are a large number of rod-shaped mullite fibers in the ceramic matrix.

Embodiment 3

[0018] 36.9% by mass of Guangxi white mud, 33.1% of industrial alumina powder, and 30% of starch are used as raw materials for batching, and 20% of ammonium bifluoride is added as an additive, mixed and ball milled for 24 hours, and formed under a pressure of 30MPa . The molded green body is kept at a temperature of 1400° C. for 2 hours to obtain fiber self-reinforced mullite porous ceramics.

[0019] The product prepared by the method of this embodiment has an apparent porosity of 60% and a bulk density of 1.44 g / cm 3 , the three-point flexural strength is 30.1MPa, and there are a large number of acicular structure mullite fibers in the ceramic matrix.

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Abstract

The invention relates to a preparation method of self-reinforced mullite porous ceramic. The preparation method comprises the following technical steps: carrying out dosing on 30-50% by mass of a mineral or solid waste containing Al2O3 and SiO2, 25-55% by mass of industrial alumina powder and 0.5-30% by mass of starch, adding 1-30% by mass of ammonium salt additives in total mass of the mixture, regulating the molar ratio of Al2O3 to SiO2 in the raw materials to be 3:2, and carrying out mixing, carrying out ball milling and forming; sintering a formed biscuit for 1-6 hours at the temperature of 1400-1600 DEG C, so as to obtain the self-reinforced mullite porous ceramic. The self-reinforced mullite porous ceramic prepared by utilizing the preparation method is in-situ fiber-reinforced mullite porous ceramic having the characteristics that mullite is taken as a primary crystalline phase, the strength is high (40-80MPa), the porosity is high (30-60%), and the aperture is small.

Description

technical field [0001] The invention belongs to the field of porous ceramic materials. In particular, it relates to a preparation method of self-reinforced mullite porous ceramics. Background technique [0002] Mullite porous ceramics are widely used in kilns because of their low cost, good thermal stability, low thermal expansion rate and thermal conductivity, high mechanical properties and excellent chemical stability. Insulation refractory materials, heat storage heat exchangers, metal filters and chemical catalytic carriers and other fields. However, most of the currently used mullite porous ceramics have disadvantages such as unreasonable pore structure, more glass phases, and relatively low flexural strength, especially for mullite porous ceramics with high porosity. It has become one of the main bottlenecks restricting its development. Therefore, in recent years, literature and patents have reported processes such as gel injection molding and in-situ synthesis of a...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C04B35/80C04B35/185C04B35/622C04B38/06
Inventor 袁磊于景坤颜正国韩露吕宁宁
Owner NORTHEASTERN UNIV
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