Preparation method of high-porosity silicon-carbide porous ceramics

A technology of porous ceramics and silicon carbide, which is applied in the field of preparation of silicon carbide porous ceramics, can solve the problems of restricting the industrial application of porous ceramics, the inability to meet the strength of applications, and the high cost of pore-forming agent raw materials, so as to achieve sufficient strength, reduce waste, and reduce The effect of raw material costs

Active Publication Date: 2012-12-05
ZHEJIANG UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0004] Although the above-mentioned patents have made good progress in porous ceramics and their applications, most porous ceramics use organic matter to form pores or in-situ reactions to form pores or foam to form pores, and a large amount of organic substances need to be added. Although the pore-forming effect is ideal, many The pore-making method cannot take into account the relationship between pore-making and densification, which often leads to high porosity, but the apparent porosity, that is, the proportion of connected pores is not high, and the strength is too low when the porosity is high, which cannot meet the strength requirements of the application.
Moreover, the raw material cost of many pore-forming agents is high, which limits their industrial application in the field of porous ceramics.

Method used

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  • Preparation method of high-porosity silicon-carbide porous ceramics

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Experimental program
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Effect test

Embodiment 1

[0040] Embodiment 1, a kind of preparation method of silicon carbide porous ceramics with high porosity, the raw material is composed of 60% silicon carbide powder, 10% boron carbide, 25% iron oxide and 5% polyvinyl alcohol , which in turn includes the following steps:

[0041] 1), mixing materials:

[0042] Using silicon carbide powder as aggregate, boron carbide as sintering aid, iron oxide as pore-forming agent, and polyvinyl alcohol as binder, add water to the raw material (the weight ratio of raw material to water is 100:120) After that, stir and mix evenly for 1 hour to make it fully mixed; obtain slurry;

[0043] Iron oxide is selected ferrous oxide for use.

[0044] 2), spray granulation:

[0045] The slurry was subjected to spray granulation, and the outlet temperature was controlled at 85° C. to obtain a powder.

[0046] 3), extrusion molding

[0047] The obtained powder is passed through extrusion molding equipment (pressure 8MPa) to prepare a biscuit (size abo...

Embodiment 2

[0060] Example 2, a preparation method of silicon carbide porous ceramics with high porosity, the raw materials are composed of 65% by weight silicon carbide powder, 10% boron carbide, 20% iron oxide and 5% polyvinyl alcohol , which in turn includes the following steps:

[0061] 1), mixing materials:

[0062] Using silicon carbide powder as aggregate, boron carbide as sintering aid, iron oxide as pore-forming agent, and polyvinyl alcohol as binder, add water to the raw material (the weight ratio of raw material to water is 100:100) After that, stir and mix evenly for 1 hour to make it fully mixed; obtain slurry;

[0063] The iron oxide is ferric oxide.

[0064] 2), spray granulation:

[0065] The slurry was subjected to spray granulation, and the outlet temperature was controlled at 84° C. to obtain a powder.

[0066] 3), extrusion molding:

[0067] The powder is passed through extrusion molding equipment (pressure 10MPa) to prepare a biscuit (size about 47.5×8×6 mm 3 )....

Embodiment 3

[0080] Example 3, a preparation method of silicon carbide porous ceramics with high porosity, the raw materials are composed of 75% by weight silicon carbide powder, 10% boron carbide, 10% iron oxide and 5% polyvinyl alcohol , which in turn includes the following steps:

[0081] 1), mixing materials:

[0082] Using silicon carbide powder as aggregate, boron carbide as sintering aid, iron oxide as pore-forming agent, and polyvinyl alcohol as binder, add water to the raw material (the weight ratio of raw material to water is 100:90) After that, stir and mix evenly for 1 hour to make it fully mixed; obtain slurry;

[0083] The iron oxide is ferric oxide.

[0084] 2), spray granulation:

[0085] The slurry was subjected to spray granulation, and the outlet temperature was controlled at 83° C. to obtain a powder.

[0086] 3), extrusion molding:

[0087] The powder is passed through the extrusion molding equipment (the pressure is 6MPa) to prepare the biscuit (the size is about...

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Abstract

The invention discloses a preparation method of high-porosity silicon-carbide porous ceramics. According to the preparation method, 60 to 80% of silicon-carbide powder, 10% of boron carbide, 5 to 25% of iron oxide and 5% of polyvinyl alcohol by weight are adopted as raw materials, and the steps of mixing, spray granulation, extrusion forming, drying and sintering are sequentially carried out, wherein the technical conditions for sintering are as follows: a dried biscuit is sintered for 10 to 15 hours at 2100 to 2200 DEG C through pressureless sintering technology so as to obtain the high-porosity silicon-carbide porous ceramics. The silicon-carbide porous ceramics prepared by the method disclosed by the invention has the characteristics of controllable aperture size, high apparent porosity, and relatively large specific surface area, and strength of the silicon-carbide porous ceramics meets the application requirement.

Description

technical field [0001] The invention relates to a preparation method of silicon carbide porous ceramics, specifically, a preparation method of silicon carbide porous ceramics with silicon carbide powder as aggregate and iron oxide as pore-forming agent. Background technique [0002] As a new type of material, porous ceramic material has a very wide range of practical application prospects. For example, it can be used as a high-temperature filter for molten metal or hot gas, for microbial filtration of clinical bacteria in medicine, as a filter membrane during chemical reactions, as a carrier for catalysts or enzymes, etc. At present, the pollution of industrial waste gas to the environment is becoming more and more serious, and its purification treatment has become an urgent problem to be solved. Therefore, the research and development of new porous ceramic materials has very important practical significance. Silicon carbide porous ceramics is a new type of functional mate...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C04B38/00C04B35/565C04B35/622
Inventor 郭兴忠朱林杨辉郑志荣
Owner ZHEJIANG UNIV
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