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Silicon nitride and silicon carbide combined composite ceramic as well as preparation method and application thereof

A technology of composite ceramics and silicon carbide, which is applied in the fields of ceramic products, applications, and other household appliances, etc., can solve the problems that composite materials do not have the performance of electromagnetic protection, achieve excellent high-temperature wave-absorbing performance, and the overall process is simple.

Active Publication Date: 2022-08-05
SHANGHAI INST OF CERAMIC CHEM & TECH CHINESE ACAD OF SCI
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  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] At present, silicon nitride combined with silicon carbide porous composite ceramic materials are mostly obtained by mixing and sintering coarse-grained silicon nitride and silicon carbide particles. This method is only obtained by building pores and material microstructures through particle gradation. Composite ceramics, although they have certain high temperature resistance performance, but the wave transmission performance of silicon nitride and the wave absorption performance of silicon carbide cancel each other out, and the composite material does not have the performance of electromagnetic protection

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  • Silicon nitride and silicon carbide combined composite ceramic as well as preparation method and application thereof
  • Silicon nitride and silicon carbide combined composite ceramic as well as preparation method and application thereof
  • Silicon nitride and silicon carbide combined composite ceramic as well as preparation method and application thereof

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preparation example Construction

[0026] The following exemplifies the preparation method of the silicon nitride combined silicon carbide composite ceramic for electromagnetic protection provided by the present invention, and the preparation method mainly includes the following steps.

[0027] Raw materials are mixed. SiC, Si and β-Si 3 N 4 The powders are uniformly mixed to form a raw material powder, and an appropriate amount of catalyst is added to the raw material powder to be uniformly mixed.

[0028] The raw material powder can be a commercial powder with a purity of >99%. In some embodiments, based on the total mass of the raw material powder being 100 wt %, the proportion of SiC powder may be 20-50 wt %; Si powder is used as a raw material for reacting with nitrogen, β-Si 3 N 4 The powder is used as a seed crystal for promoting grain growth, and the total content of the two can be 50-80 wt %. Among them, β-Si 3 N 4 The powder can account for 1-10wt% of its total mass with Si powder.

[0029] Pr...

Embodiment 1

[0047] Take 5g and 15g of SiC powder with a median particle size of 0.1 microns and 5 microns, respectively, 75 g of Si powder with a median particle size of 0.5 microns, and β-Si with a median particle size of 3 microns. 3 N 4 Mix 5g powder and 0.1g molybdenum oxide powder. 80g of PVB powder is used as a binder, which is thoroughly mixed and dissolved with 260g of alcohol. 200g of silicon carbide grinding balls and the aforementioned powder are ball-milled and mixed in a planetary ball mill for 4 hours at a rotational speed of 300r / min to obtain a slurry with uniform composition. After drying, the slurry is passed through a 200-mesh sieve to obtain a mixed powder with uniform components, which is dry-pressed into a green sample with a length of 40mm*width 8mm*8mm high, and the molding pressure is 0.07MPa. The degreasing process is as follows: the green body is heated from 300 ° C to 600 ° C, and the heating time is controlled to 3 hours to ensure the full decomposition of th...

Embodiment 2

[0051] Take 5g and 15g of SiC powder with a median particle size of 0.1 microns and 5 microns, respectively, 75 g of Si powder with a median particle size of 0.5 microns, and β-Si with a median particle size of 3 microns. 3 N 4 Mix 5g powder and 0.1g molybdenum oxide powder. 30g of PVB powder is used as a binder, which is thoroughly mixed and dissolved with 130g of alcohol. 200g of silicon carbide grinding balls and the aforementioned powder are ball-milled and mixed in a planetary ball mill for 6 hours at a rotational speed of 300r / min to obtain a slurry with uniform composition. After drying, the slurry is passed through a 200-mesh sieve to obtain a mixed powder with uniform components, which is dry-pressed into a blank sample of φ60mm*10mm with a molding pressure of 0.1MPa and degreasing. The degreasing process is: The temperature was raised to 600°C, and the heating time was controlled to 1 hour to ensure the sufficient decomposition of the binder and the integrity of the...

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Abstract

The invention relates to a silicon nitride combined silicon carbide composite ceramic and a preparation method and application thereof. The preparation method comprises the following steps: mixing SiC, Si and beta-Si3N4 powder to form raw material powder, and adding a catalyst capable of promoting nitridation of the Si powder to generate beta-phase Si3N4 rod-like crystal grains; on the basis that the total mass of the raw material powder is 100 wt%, the SiC powder accounts for 20-50 wt%, the sum of the Si powder and the beta-Si3N4 accounts for 50-80 wt%, and the beta-Si3N4 powder accounts for 1-10 wt% of the total mass of the Si powder and the beta-Si3N4 powder; the dosage of the catalyst is 0.1-1wt% of the total mass of the raw material powder; dissolving a binder in an organic solvent to form a binder solution, and ball-milling and uniformly mixing the raw material powder, the catalyst and the binder solution to prepare slurry; the slurry is dried, sieved and molded into a biscuit, and the biscuit is degreased and sintered to obtain the silicon nitride combined silicon carbide composite ceramic.

Description

technical field [0001] The invention belongs to the technical field of ceramic material preparation, and in particular relates to a silicon nitride combined silicon carbide composite ceramic and a preparation method and application thereof. Background technique [0002] Silicon carbide is a typical covalent bond compound. Silicon carbide ceramics have the characteristics of excellent mechanical properties, good thermal stability, etc., and their dielectric constant is adjustable within a certain range. The excellent properties of silicon carbide ceramics make it an excellent candidate for absorbing materials in the field of electromagnetic wave protection. Silicon nitride ceramics have high mechanical strength, excellent thermodynamic properties, excellent high-temperature mechanical properties and impact resistance, and have great application potential in the field of a new generation of high-temperature wave-transmitting materials. [0003] Silicon nitride combined with s...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C04B38/06C04B38/00C04B35/591C04B35/587
CPCC04B38/067C04B35/587C04B35/591C04B38/0022C04B2235/5436C04B2235/3826C04B2235/428C04B2235/3882C04B2235/3256C04B38/0074
Inventor 杨晓刘学建姚秀敏张辉黄政仁
Owner SHANGHAI INST OF CERAMIC CHEM & TECH CHINESE ACAD OF SCI
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