Preparation method of silicon nitride and silicon carbide combined lanthanum hexaboride foamed ceramic

A technology of lanthanum hexaboride and foam ceramics, which is applied in the field of porous ceramic preparation, can solve the problems of poor thermal shock resistance, low service temperature, and inability to meet the needs of continuous casting of large special steel castings, and achieve excellent thermal shock resistance , strength improvement, light weight effect

Inactive Publication Date: 2015-01-28
SHANDONG UNIV OF TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The currently used alumina foam ceramics and lanthanum hexaboride foam ceramics generally have problems such as low operating temperature and poor thermal shock resistance, which cannot meet the needs of continuous casting of large special steel castings.

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0010] LaB 6 , silicon micropowder, and phenolic resin are mixed uniformly with a weight ratio of 40:40:20 and an additional concentration of 0.1wt% hydroxypropyl methylcellulose solution 40wt% to make a ceramic slurry, and then the ceramic slurry is impregnated in polyurethane On the foam, after drying, in a nitrogen atmosphere, slowly heat up at a temperature of 300 ° C ~ 1450 ° C for 20 hours, at a temperature of 1450 ° C for 5 hours, and then in a vacuum or argon atmosphere, at a temperature of 1700 ° C for 20 minutes to make nitriding Silicon, silicon carbide combined with lanthanum hexaboride foam ceramics.

[0011] The purity of the batching raw materials used in the experiment is industrial pure.

Embodiment 2

[0013] LaB 6 , microsilica powder, and phenolic resin are uniformly mixed with a weight ratio of 60:25:15 and an additional concentration of 0.2wt% hydroxypropyl methylcellulose solution 50wt% to make a ceramic slurry, and then the ceramic slurry is impregnated in polyurethane On the foam, after drying, slowly heat up for 60 hours at a temperature of 300°C to 1450°C in a nitrogen atmosphere, keep it at 1450°C for 8 hours, and then hold it at a temperature of 1730°C for 70 minutes in a vacuum or argon atmosphere to make nitriding Silicon, silicon carbide combined with lanthanum hexaboride foam ceramics.

[0014] The purity of the batching raw materials used in the experiment is industrial pure.

Embodiment 3

[0016] LaB 6 , silicon micropowder, and phenolic resin are uniformly mixed with a weight ratio of 88:10:2 and an additional concentration of 0.3wt% hydroxypropyl methylcellulose solution 60wt% to make a ceramic slurry, and then the ceramic slurry is impregnated in polyurethane On the foam, after drying, in a nitrogen atmosphere, slowly heat up at a temperature of 300°C~1450°C for 100 hours, keep at a temperature of 1450°C for 10 hours, and then hold at a temperature of 1750°C for 120 minutes in a vacuum or argon atmosphere to make silicon nitride , Silicon carbide combined with lanthanum hexaboride foam ceramics.

[0017] The purity of the batching raw materials used in the experiment is industrial pure.

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PUM

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Abstract

The invention discloses a preparation method of a silicon nitride and silicon carbide combined lanthanum hexaboride foamed ceramic. The preparation method is characterized by comprising the following steps: uniformly mixing LaB6, silica powder, phenolic resin and hydroxypropyl methyl cellulose solution to prepare ceramic slurry, soaking the ceramic slurry in a polyurethane foam, drying and sintering in nitrogen atmosphere to prepare the silicon nitride and silicon carbide combined lanthanum hexaboride foamed ceramic. The prepared silicon nitride and silicon carbide combined lanthanum hexaboride foamed ceramic has a uniform microscopic structure, high strength and uniform hole size, and is capable of avoiding the residue of carbon and free silicon so as to greatly improve the strength, the high temperature resistance and the thermal shock resistance.

Description

technical field [0001] The invention relates to silicon nitride, silicon carbide combined with lanthanum hexaboride foam ceramics, belonging to the technical field of porous ceramic preparation. Background technique [0002] Silicon nitride, silicon carbide combined with lanthanum hexaboride composite ceramic is a structural ceramic material with low expansion, corrosion resistance, high strength and high temperature resistance. Silicon nitride, silicon carbide and lanthanum hexaboride foam ceramics are mainly used as molten steel filter elements in steel casting and other industries for large special steel castings. The currently used alumina foam ceramics and lanthanum hexaboride foam ceramics generally have problems such as low operating temperature and poor thermal shock resistance, which can no longer meet the needs of continuous casting of large special steel castings. Contents of the invention [0003] The object of the present invention is to provide a kind of pre...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C04B38/00C04B35/50C04B35/58C04B35/565C04B35/584C04B35/622
Inventor 唐竹兴
Owner SHANDONG UNIV OF TECH
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