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Boron nitride-silicon nitride sandwich wide-frequency wave-transmitting material and preparation method thereof

A wave-transmitting material, boron nitride technology, applied in ceramic products, other household utensils, applications, etc., can solve the problems of low atomic diffusion coefficient, excessive grain growth, and difficult sintering, etc., to achieve adjustable material microstructure, The heating rate is fast and the effect of grain growth can be controlled

Active Publication Date: 2019-01-18
NAT UNIV OF DEFENSE TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Nitride ceramics have high covalent bond energy such as B-N and Si-N, and low atomic diffusion coefficient. Without adding sintering aids, it is difficult to achieve sintering at low temperature by using traditional sintering methods, and it is more difficult to achieve sintering at high temperatures. Long holding time causes excessive growth of grains; and its microstructure (pores, grain boundaries, grain size, etc.) has a profound impact on the mechanical, dielectric and wave-transmitting properties of ceramics
In addition, interlayer materials are prone to cracking due to uneven shrinkage during conventional sintering

Method used

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  • Boron nitride-silicon nitride sandwich wide-frequency wave-transmitting material and preparation method thereof
  • Boron nitride-silicon nitride sandwich wide-frequency wave-transmitting material and preparation method thereof
  • Boron nitride-silicon nitride sandwich wide-frequency wave-transmitting material and preparation method thereof

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preparation example Construction

[0042] A method for preparing a boron nitride-silicon nitride interlayer broadband wave-transmitting material of the present invention comprises the following steps:

[0043] S1. Mix the polymer monomer, crosslinking agent, dispersant, pore forming agent and deionized water to obtain a mixed solution; use silicon nitride ceramic powder and sintering aid I as the mixed solid phase, and add it to the mixed solution Perform ball milling pretreatment to obtain premixed slurry;

[0044] S2. Add a pH regulator to the premixed slurry obtained in step S1 until the pH value is 8.5 to 11.5, and ball mill to obtain a mixed slurry. The mixed slurry is vacuum degassed under stirring conditions, and an initiator is added for mixing. Obtain injection molding slurry;

[0045] S3. Perform injection molding on the injection molding slurry obtained in step S2, and perform demoulding, drying, and debinding treatment after the slurry is completely solidified to obtain a porous silicon nitride gre...

Embodiment 1

[0050] A method for preparing a boron nitride-silicon nitride interlayer broadband wave-transmitting material in this embodiment includes the following steps:

[0051] S1. Add 7g of acrylamide, 0.3g of N'N-methylenebisacrylamide, 400μL of dispersant JA-281 (density 1.06g / mL) and 10g of pore-forming agent n-hexane into 60mL of deionized water to form a mixed solution , then 100g silicon nitride ceramic powder, 3g sintering aid (Al 2 o 3 with SiO 2 Mass ratio 1:1) mixed with the prepared mixed solution, and ball milled for 60 minutes to obtain pre-mixed slurry;

[0052] S2. Add tetramethylammonium hydroxide to the premixed slurry obtained in step S1 until the pH of the premixed slurry is 9.8, and continue ball milling for 4 hours to obtain a mixed slurry; then stir and pump at a speed of 800r / min Remove the gas in the mixed slurry by vacuum, then add 2.44mL initiator (the aqueous solution of 2,2'-azo(2-methylpropyl ether) dihydrochloride with a mass fraction of 15% is used in...

Embodiment 2

[0065] The preparation method of the present embodiment is roughly the same as that of Example 1, except that:

[0066] In step S4, the sintering temperature is 1850° C., and the sintering pressure is 20 MPa.

[0067] Finally, a non-stripping boron nitride-silicon nitride interlayer broadband wave-transmitting material can be obtained.

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Abstract

The invention discloses a preparation method for a boron nitride-silicon nitride sandwich wide-frequency wave-transmitting material. The preparation method comprises the following steps: taking silicon nitride ceramic powder as a raw material, adopting a gel injection-moulding method to prepare a porous silicon nitride blank; spreading a boron nitride powder mixture on upper and lower surfaces ofthe porous silicon nitride blank, and sintering through a discharge plasma sintering process to obtain sandwich ceramic; performing decarbonizing treatment on the sandwich ceramic to obtain the boronnitride-silicon nitride sandwich wide-frequency wave-transmitting material. The boron nitride-silicon nitride sandwich wide-frequency wave-transmitting material prepared by the preparation method is not liable to crack, good in interlayer combination, and adjustable in microstructure, and can be applied to wave-transmitting parts such as a high-temperature wide-frequency antenna cover.

Description

technical field [0001] The invention relates to the field of high-temperature wave-transmitting composite materials, in particular to a boron nitride-silicon nitride interlayer broadband wave-transmitting material and a preparation method thereof. Background technique [0002] Anti-radiation missiles have gradually become an important means of suppressing air defense systems, seizing battlefield electromagnetic advantages, and giving full play to the effectiveness of air strike weapons and equipment in modern high-tech warfare. Its seeker needs to work in a wide frequency range to cover the radar operating frequency (0.1-40 GHz), which requires it to have good broadband wave-transmitting performance; while the missile is subjected to aerodynamic loads and environmental conditions during high-speed flight. Particles, rain erosion and other harsh environments; at the same time, the radar guidance system must meet the electrical performance requirements such as power transfer c...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C04B35/584C04B35/5835C04B35/622C04B38/00C04B35/645
CPCC04B35/583C04B35/584C04B35/622C04B35/645C04B38/00C04B2235/6562C04B2235/666C04B2235/3409C04B2235/3225C04B2235/3217
Inventor 李端李斌于秋萍高世涛杨雪金侯寓博
Owner NAT UNIV OF DEFENSE TECH
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