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High-temperature-resistant high-strength tough silicon nitride based wave-transparent composite material and preparation method thereof

A high-strength and toughness, silicon nitride-based technology, used in ceramic products, antennas, applications, etc., can solve the problems of insufficient strength, toughness and wave transmittance of basic wave-transmitting materials, and cannot meet the requirements of high Mach number aircraft. It has strong designability, improves and optimizes performance, and meets the effect of anti-oxidation

Active Publication Date: 2018-02-16
NORTHWESTERN POLYTECHNICAL UNIV
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  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0008] In order to avoid the deficiencies of the prior art, the present invention proposes a high-temperature-resistant, high-strength, toughness silicon nitride-based wave-transmitting composite material and its preparation method to solve the problem of existing Si 3 N 4 In order to provide a high-performance Si 3 N 4 Whisker reinforced BN / Si 3 N 4 Preparation method of gel injection molding combined with CVI technology for wave-transparent composite materials

Method used

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  • High-temperature-resistant high-strength tough silicon nitride based wave-transparent composite material and preparation method thereof
  • High-temperature-resistant high-strength tough silicon nitride based wave-transparent composite material and preparation method thereof

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preparation example Construction

[0027] Step 1.Si 3 N 4 Preparation of whisker blank: the volume fraction is 20-50% Si 3 N 4 Whiskers and 1.5-2.5wt.% of the dispersant polyacrylamine are dissolved in deionized water, and the pH regulator tetramethylammonium hydroxide is added to adjust the pH value of the slurry to 9-11; after that, 4-10wt.% of Monomer acrylamide (AM) and 0.2-1.0wt.% cross-linking agent methylenebisacrylamide (MBAM), ball mill the slurry for 24-36 hours, and vacuum defoam for 10 minutes after mixing evenly; then add 0.2-0.5 wt.% of the initiator ammonium persulfate and 0.02-0.1wt.% of the catalyst tetramethylethylenediamine (TEMED), stirred evenly, poured into a mold, and formed into Si 3 N 4 Whisker blanks.

[0028] Step 2. Si 3 N 4 Drying of the whisker blank: the Si in step 1 3 N 4 The whisker blank is naturally dried at room temperature for 12-36 hours, and then dried in an oven at 50-100°C.

[0029] Step 3. Si 3 N 4 Debinding of the whisker blank: the Si in step 2 3 N 4 The...

Embodiment 1

[0033] Step 1. Si 3 N 4 Preparation of whisker green body: the volume fraction of 30% Si 3 N 4 Whiskers, 1.5wt.% dispersant polyacrylamide were dissolved in deionized water, the pH regulator was tetramethylammonium hydroxide, the pH value was 11, and then 5wt.% monomer AM, 0.25wt.% The cross-linking agent MBAM was ball-milled for 24 hours, the slurry was mixed evenly, and after vacuum defoaming for 10 minutes, 0.4wt.% of the initiator APS and 0.02wt.% of the catalyst TEMED were added, stirred evenly and poured into the mold to obtain Si 3 N 4 Whisker blank;

[0034] Step 2. Si 3 N 4 Drying of the whisker blank: the whisker blank in step 1 was naturally dried at room temperature for 36 hours, and then dried in an oven at 80°C;

[0035] Step 3. Si 3 N 4 Debinding of whisker blanks: put the dried blanks in a horse-boiler furnace, and empty-fire debinding at 500°C for 3 hours to obtain Si 3 N 4 Whisker preform;

[0036] Step 4. Preparation of BN interface: use CVI proc...

Embodiment 2

[0039] Step 1.Si 3 N 4 Preparation of whisker green body: Si with a volume fraction of 35% 3 N 4 Whiskers, 1.5wt.% dispersant polyacrylamide were dissolved in deionized water, the pH regulator was tetramethylammonium hydroxide, the pH value was 11, and then 5wt.% monomer AM, 0.25wt.% The cross-linking agent MBAM was ball-milled for 28 hours, the slurry was mixed evenly, and after vacuum defoaming for 10 minutes, 0.35wt.% of the initiator APS and 0.02wt.% of the catalyst TEMED were added, stirred evenly, and poured into the mold to obtain Si 3 N 4 Whisker blank;

[0040] Step 2. Si 3 N 4 Drying of the whisker blank: the whisker blank in step 1 was naturally dried at room temperature for 36 hours, and then dried in an oven at 80°C;

[0041] Step 3. Si 3 N 4 Debinding of whisker blanks: put the dried blanks in a horse-boiler furnace, and empty-fire debinding at 500°C for 3 hours to obtain Si 3 N 4 Whisker preform;

[0042] Step 4. Preparation of BN interface: use CVI ...

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Abstract

The invention relates to a high-temperature-resistant high-strength tough silicon nitride based wave-transparent composite material and a preparation method thereof. The preparation method comprises the following steps: preparing a porous Si3N4 whisker biscuit through gel casting, and performing drying and rubber discharging to obtain a porous Si3N4 preform; and preparing a boron nitride (BN) interface in the whisker preform through a chemical vapor infiltration (CVI) process, and preparing a multilayer alternate BN / Si3N4 matrix through the CVI process. In accordance with the design requirements for the structure and performance of a high-temperature wave-transparent antenna housing, the microstructure of each layer, the number of layers and the layer thickness of the multilayer alternateBN / Si3N4 matrix are regulated and controlled through CVI regulation and control to realize the regulation, control and optimization of the structure and performance of the composite material, therebyobtaining the high-temperature-resistant high-strength high-toughness Si3N4 based wave-transparent composite material which realizes broadband wave transmission and has excellent thermophysical properties.

Description

technical field [0001] The invention belongs to the silicon nitride-based wave-transparent composite material technology, and relates to a silicon nitride-based wave-transparent composite material with high temperature resistance and high strength and toughness and a preparation method thereof. Background technique [0002] The radome is an important structural part to protect the communication, telemetry, guidance, detonation and other systems of missiles and other spacecraft from environmental influences under harsh environmental conditions. It has been widely used in radio systems such as missiles, radars and satellites. The modern military has an urgent demand for high Mach number (Ma≥8) missiles and other aircraft, and then puts forward more stringent requirements for the use of radomes. The performance of the radome directly depends on the selected material. In order to realize the high Mach flight and precise guidance of the aircraft, the radome material must be able ...

Claims

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Application Information

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IPC IPC(8): C04B35/81C04B35/584C04B35/634C04B35/632C04B35/624C04B38/00C04B41/89H01Q1/42
CPCC04B35/584C04B35/624C04B35/632C04B35/63444C04B35/806C04B38/0045C04B41/009C04B41/52C04B41/89H01Q1/422C04B41/5064C04B41/5066
Inventor 刘永胜叶昉陈乃齐成来飞李明星张立同
Owner NORTHWESTERN POLYTECHNICAL UNIV
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