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a porous si 2 no 2 o High temperature resistant wave transparent ceramics and preparation method thereof

A technology of high temperature resistance and ceramics, which is applied in the field of porous Si2N2O high temperature resistant wave-transmitting ceramics and its preparation. It can solve the problems of large shrinkage, low strength, and inability to prepare large-sized workpieces, and achieve excellent thermal shock resistance and high strength.

Active Publication Date: 2020-07-21
HARBIN INST OF TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

The gel strength prepared by using water as a solvent is relatively high, but it shrinks greatly during the drying process, and it is impossible to prepare a high-porosity ceramic body, and the Si 3 N 4 It will be slowly hydrolyzed in water; the gel prepared by organic solvent has small drying shrinkage, and can prepare ceramic green body with high porosity, but the commonly used organic solvents can not dissolve the gel, and its polymerization reaction is precipitation polymerization, resulting in The degree of polymerization of the gel is low, the strength is low, and it is impossible to prepare large-sized workpieces

Method used

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  • a porous si <sub>2</sub> no <sub>2</sub> o High temperature resistant wave transparent ceramics and preparation method thereof
  • a porous si <sub>2</sub> no <sub>2</sub> o High temperature resistant wave transparent ceramics and preparation method thereof
  • a porous si <sub>2</sub> no <sub>2</sub> o High temperature resistant wave transparent ceramics and preparation method thereof

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Embodiment 1

[0030] This embodiment provides a porous Si 2 N 2 O the preparation method of high temperature resistant wave-transparent ceramics, it may further comprise the steps:

[0031] Step 1: Add Li to Ethylene Glycol 2 CO 3 , polyethylene glycol, acrylamide and N,N-methylenebisacrylamide, with Si 3 N 4 Ball milling and mixing for 24 hours to obtain a slurry, wherein the ceramic powder is Si 3 N 4 and SiO 2 The mixed powder, and the Si 3 N 4 and the SiO 2 The mass ratio of the ceramic powder is 1:0.42; the volume ratio of the ceramic powder to the ethylene glycol is 1:8; the Li 2 CO 3 The mass ratio to the ceramic powder is 1:19; the mass ratio of the polyethylene glycol to the ceramic powder is 1:98; the mass ratio of the acrylamide to the ceramic powder is 1 :8; the mass ratio of the N,N-methylenebisacrylamide and the ceramic powder is 1:200;

[0032] The second step: slowly stir the slurry described in the first step in a vacuum box of 100 Pa for 5 minutes to defoam, t...

Embodiment 2

[0043] The difference between this embodiment and embodiment 1 is that the ceramic powder in the first step is Si 3 N 4 and SiO 2 The mixed powder, and the Si 3 N 4 and the SiO 2 The mass ratio of the ceramic powder is 1:0.43; the volume ratio of the ceramic powder to the ethylene glycol is 1:1.5; the Li 2 CO 3 The mass ratio to the ceramic powder is 1:12; the mass ratio of the polyethylene glycol to the ceramic powder is 1:49; the mass ratio of the acrylamide to the ceramic powder is 1 :5; the mass ratio of the N,N-methylenebisacrylamide to the ceramic powder is 1:125, and the others are the same as in Example 1.

Embodiment 3

[0045] The difference between this embodiment and embodiment 1 is that the ceramic powder in the first step is Si 3 N 4 and SiO 2 The mixed powder, and the Si 3 N 4 and the SiO 2 The mass ratio of the ceramic powder is 1:0.43; the volume ratio of the ceramic powder to the ethylene glycol is 1:9; the Li 2 CO 3 The mass ratio to the ceramic powder is 1:32; the mass ratio of the polyethylene glycol to the ceramic powder is 1:99; the mass ratio of the acrylamide to the ceramic powder is 1 :9; the mass ratio of the N,N-methylenebisacrylamide to the ceramic powder is 1:270, and the others are the same as in Example 1.

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Abstract

The invention provides porous Si2N2O high temperature-resistant wave-permeable ceramics and a preparation method thereof. The preparation method comprises the following steps of adding ceramic powder,a sintering aid, a dispersant, a monomer and a crosslinking agent in an organic solvent, performing ball milling mixing to obtain a slurry, removing bubbles, adding an initiator and a catalyst, performing solvent exchange to obtain a porous Si2N2O green body, and finally, performing gas pressure sintering to obtain the porous Si2N2O high temperature-resistant wave-permeable ceramics. Compared with the prior art, the porous Si2N2O high temperature-resistant wave-transparent ceramics have the beneficial effects that by using ethylene glycol as a solution to prepare the porous Si2N2O ceramics, the low surface tension of ethylene glycol ensures relatively small drying shrinkage of gel, so that the Si2N2O ceramics with high porosity can be acquired; and in addition, polymerization of the gel in ethylene glycol is solution polymerization, so that high strength of the green body is ensured, and the near-net formation of a large-size workpiece. Therefore, the prepared porous Si2N2O ceramic material has excellent thermal shock resistance, oxidation resistance and wave-permeable performance and is a good high temperature-resistant wave-permeable material with excellent comprehensive properties of power, heat and electricity.

Description

technical field [0001] The invention relates to the technical field of preparation of high-temperature-resistant wave-transmitting ceramic materials, in particular to a porous Si 2 N 2 O high temperature resistant wave transparent ceramics and its preparation method. Background technique [0002] The main application fields of high temperature resistant and wave-transparent materials are radome and antenna window of missiles and spaceships. and wave-transparent performance. [0003] The commonly used radome and antenna window material is SiO 2 、Si 3 N 4 and Sialon ceramics. Among them, SiO 2 Ceramics have excellent wave-transmitting properties and can serve in medium and low temperature (below 1200°C) environments, but their mechanical properties are poor; Si 3 N 4 And Sialon ceramics have good mechanical properties and high temperature (1200-1500°C) stability, but the wave transmission performance is average (dielectric constants are 7.9 and 8.5, respectively), and...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C04B35/597C04B35/622C04B35/624C04B38/00
CPCC04B35/597C04B35/622C04B35/624C04B38/0045C04B2235/3418C04B2235/3873C04B2235/6023C04B2235/606C04B2235/656C04B2235/6562C04B2235/6567C04B2235/658
Inventor 叶枫金义程刘强张标高晔
Owner HARBIN INST OF TECH