Method for preparing porous silicon nitride wave transmitting ceramic with low dielectric constant and high strength

A silicon nitride wave-transparent and low-dielectric constant technology, which is applied in the preparation of high-strength porous silicon nitride wave-transparent ceramics and low-dielectric constant fields, can solve the problem of difficult control of pore distribution uniformity, large pore size, and complex methods etc. to achieve the effect of low cost, high porosity and simple method

Inactive Publication Date: 2011-01-26
AEROSPACE RES INST OF MATERIAL & PROCESSING TECH +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The above methods all use the pore-forming agent method to form pores, and the pore-forming agent must be removed during the sintering process, resulting in large pore size and difficult to control the uniformity of pore distribution
At the same time, the method is complicated and the cost is high

Method used

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  • Method for preparing porous silicon nitride wave transmitting ceramic with low dielectric constant and high strength
  • Method for preparing porous silicon nitride wave transmitting ceramic with low dielectric constant and high strength
  • Method for preparing porous silicon nitride wave transmitting ceramic with low dielectric constant and high strength

Examples

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Effect test

Embodiment 1

[0024] Weighing 90 grams of silicon nitride powder, the particle size of the silicon nitride is 0.3-3 microns, the alpha phase content is greater than 93%, and the purity is greater than 99.9%. Add 5 grams of aluminum oxide and 5 grams of yttrium oxide, wherein the average particle size of aluminum oxide is 0.3 microns, the purity is greater than 99.8%, and the particle size of yttrium oxide is 1-10 microns, and the purity is greater than 99%. The three are mixed, with the analysis of pure alcohol as the medium, adding 30% of the total mass of the powder, using agate balls as grinding balls, powder: agate balls=1: 2 (mass ratio), and mixing for 12 hours to make the material pulp, dried to make dry powder, and sieved. Then put the mixed powder into a mold with a diameter of 60mm, pressurize and shape at 50MPa, and sinter the formed green body at 1600°C under a vacuum / nitrogen protective atmosphere. The specific sintering process is carried out in stages: below 800°C, the heati...

Embodiment 2

[0028] Weighing 85 grams of silicon nitride powder, the particle size of the silicon nitride is 0.3-3 microns, the alpha phase content is greater than 93%, and the purity is greater than 99.9%. Add 10 grams of yttrium oxide and 5 grams of silicon oxide, wherein the particle size of the yttrium oxide is 1-10 microns, the purity is greater than 99%, the purity of the silicon oxide is more than 99%, and the average particle size is less than 100 nanometers. Mix the three, use pure alcohol as the medium, add 60% of the total mass of the powder, use agate balls as the grinding balls, powder: agate balls=1:2 (mass ratio), and mix the materials for 24 hours to make the material pulp, dried to make dry powder, and sieved. Then put the mixed powder into a mold with a diameter of 60mm, pressurize and shape at 70MPa, and sinter the formed body at 1700°C under a vacuum / nitrogen protective atmosphere. The specific sintering process is carried out in stages: below 800°C, the heating rate i...

Embodiment 3

[0032] Weighing 85 grams of silicon nitride powder, the particle size of the silicon nitride is 0.3-3 microns, the alpha phase content is greater than 93%, and the purity is greater than 99.9%. Add 10 grams of yttrium oxide and 5 grams of aluminum oxide, wherein the particle size of yttrium oxide is 1-10 microns, the purity is greater than 99%, the purity of silicon oxide is >99%, and the average particle size is <100 nanometers. The three are mixed, with the analysis of pure alcohol as the medium, add by 40% of the total mass of the material powder, use the agate ball as the grinding ball, the material powder: agate ball=1: 2 (mass ratio), and mix the materials for 20 hours to make the material pulp, dried to make dry powder, and sieved. Then put the mixed powder into a mold with a diameter of 60mm, pressurize and shape at 100MPa, and sinter the formed green body at 1800°C under a vacuum / nitrogen protective atmosphere. The specific sintering process is carried out in stages:...

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Abstract

The invention discloses a method for preparing a porous silicon nitride wave transmitting ceramic with low dielectric constant and high strength. The method comprises the following steps of: (1) proportioning: uniformly mixing 80-90 weight percent of silicon nitride powder and 10-20 weight percent of metallic oxide to obtain a powder mixture; (2) mixing: adding absolute ethanol in an amount which is 30 to 60 percent based on the total mass of the material-powder mixture, and mixing the material-powder mixture and agate balls in the mass ratio of 1:2 for 12 to 24 hours to obtain the wet mixed material, wherein the agate balls are taken as mill balls; (3) forming: drying the wet mixed material, then sieving the mixed material with a screen, and performing compression forming to obtain a blank; and (4) sintering: sintering the blank in a protective atmosphere to obtain the porous silicon nitride wave transmitting ceramic. The method does not need a special pore former; a pore is formed by overlapping the columnar silicon nitride; and the method has the advantages of uniform and diffused pore, simplicity and low cost.

Description

technical field [0001] The invention belongs to the preparation technology of special functional ceramics, and in particular relates to a preparation method of low dielectric constant, high-strength porous silicon nitride wave-transparent ceramics. Background technique [0002] Porous ceramics are a class of ceramic materials in which the gas phase is the main phase. Normally, the pores in the material, including closed pores and open pores, are occupied by air, and the dielectric constant of air is generally close to 1, and the loss tangent value is even closer to 0, so the larger the porosity, the better the material The lower the dielectric constant and loss tangent value, that is, in the process of wave transmission, the reflection and heat loss are reduced, and the wave transmittance is increased. [0003] Silicon nitride ceramics is one of the materials with the best comprehensive performance in structural ceramics. It not only highlights the advantages of general cer...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C04B35/622C04B38/00C04B35/584
Inventor 张健张大海王红洁余娟丽
Owner AEROSPACE RES INST OF MATERIAL & PROCESSING TECH
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