Method for preparing porous beta-SiAlON ceramic

A technology of ceramics and N elements, applied in the field of preparation of porous ceramic materials, can solve the problems of hydrolysis of AlN raw materials, uneven distribution of pore structure, and inability to control porosity, etc., and achieve the effect of meeting the requirements of dielectric properties

Inactive Publication Date: 2012-12-05
HARBIN INST OF TECH
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  • Abstract
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Problems solved by technology

[0007] The purpose of the present invention is to solve the problem that the existing porous β-SiAlON ceramics prepared by partial sintering method have uneven distribution of pore structure and cannot control the porosity, and provide a preparation method of porous β-SiAlON ceramics
[0009] Advantages of the present invention: 1. The present invention uses alkenes instead of traditional water as a solvent, which solves the problem of AlN raw materials being hydrolyzed in water; 2. The present invention prepares porous β-SiAlON ceramic materials by condensation molding technology, breaking through the traditional The process is limited in the preparation of complex components and harsh drying conditions. By controlling the solid phase content (that is, the volume ratio of alkene to the mixed powder, the mixed powder is Si 3 N 4 Powder, Al 2 o 3 powder and AlN powder mixture) to control the porosity, and prepared high-strength β-SiAlON porous ceramic materials with different porosities, the porosity is 36%~71%, and the resistance of the ceramic material is 36% when the porosity is 36%. The flexural strength is 306MPa; 3. The present invention can obtain β-SiAlON porous ceramic materials with different porosities by adjusting the solid phase content of the slurry, and the dielectric constant is 3.5~5.6, which is much smaller than that of dense silicon nitride based ceramics. The electrical constant meets the requirements for dielectric properties in practical applications

Method used

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  • Method for preparing porous beta-SiAlON ceramic

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specific Embodiment approach 1

[0011] Embodiment 1: This embodiment is a preparation method of porous β-SiAlON ceramics, which is specifically completed according to the following steps: 1. Prepare materials: according to the chemical formula Si 6-z Al z o z N 8-z , weigh Si according to the ratio of Si element, Al element, O element and N element molar ratio of 6-z:z:z:8-z 3 N 4 Powder, Al 2 o 3 powder and AlN powder; two, preparation of mixed powder: first with Si 3 N 4 The ball is a grinding ball, with absolute ethanol as the ball milling medium, the Si 3 N 4 Powder, Al 2 o 3 The powder and AlN powder were wet-mixed by ball mill for 18h~22h, and the mixed powder was obtained after drying through a 200-mesh sieve; 3. Preparation of SiAlON-β-SiAlON slurry: firstly, put the SiAlON, dispersant and mixed powder in a ball mill tank , and then ball milled at a temperature of 55°C~65°C for 12h~24h to obtain a uniform and stable alkene-β-SiAlON slurry; 4. Condensation: first preheat the polyethylene mo...

specific Embodiment approach 2

[0021] Embodiment 2: The difference between this embodiment and Embodiment 1 is that the dispersant described in Step 3 is Deqian 923S wetting and dispersing agent. Others are the same as the first embodiment.

[0022] The mixture of Deqian 923S wetting and dispersing agent Sergio electrically neutral polycarboxylate amine salt and modified polysiloxane described in this embodiment is operated by Guangzhou Jinhong Chemical Co., Ltd. The slurry of β-SiAlON original powder with alkenes as the solvent can improve the slurry stability and solid phase content of the slurry, so this embodiment chooses the Deqian 923S wetting and dispersing agent as the dispersant of this embodiment.

specific Embodiment approach 3

[0023] Embodiment 3: The difference between this embodiment and Embodiment 1 or 2 is that the cooling source described in step 4 is ice water, alcohol at a temperature of -60°C~-30°C, or alcohol at a temperature of -185°C Liquid nitrogen at ~-180°C. Others are the same as those in Embodiment 1 or 2.

[0024] Adopt following test to verify effect of the present invention:

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Abstract

A method for preparing porous beta-SiAlON ceramic relates to a method for preparing porous ceramic. The method aims to solve the problem that the porous beta-SiAlON ceramic prepared by an existing partially sintering method is not uniform in distribution of pore structures and uncontrollable in poriness. The method includes the steps of firstly, preparing materials according to the chemical formula Si6-zAlzOzN8-z; secondly, mixing by ball milling to obtain mixed powder; thirdly, subjecting camphene, dispersing agent and the mixed powder to ball-milling to obtain uniform and stable camphene-beta-SiAlON slurry; fourth, condensing to obtain concretionary camphene-beta-SiAlON; fifthly, drying to obtain dried camphene-beta-SiAlON; and sixthly, pressurelessly sintering to obtain the porous beta-SiAlON ceramic. The method is mainly used for preparing porous beta-SiAlON ceramic.

Description

technical field [0001] The invention relates to a preparation method of a porous ceramic material. Background technique [0002] With the development of technology and the increase of flight speed of aircraft, higher requirements are put forward for the performance of various aerospace vehicle radomes. The high temperature strength and dielectric properties of inorganic materials endow them with sufficient competitiveness in the application of high-speed missiles. It has been widely used in anti-aircraft missiles with a Mach number of about 3. Si 3 N 4 With its excellent mechanical properties at room temperature and high temperature, and good thermal shock resistance, ceramics have become an attractive radome material. By controlling the porosity of silicon nitride, various foam-like materials with different densities and different dielectric constants can be obtained. Silicon nitride can be used to manufacture missile radomes with high temperature resistance up to 1600°C...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C04B35/622C04B35/599
Inventor 叶枫侯赵平刘强刘利盟张海礁
Owner HARBIN INST OF TECH
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