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Preparation method of high-temperature wave-transparent silicon nitride radome

A high-temperature wave-transmitting and radome technology, which is applied in the direction of the radiation unit cover, can solve the problems of low toughness of the radome, difficult machining, poor formability, etc., and achieve high ablation resistance, mechanical properties and broadband wave-transmitting performance Excellent, high preform rigidity effect

Inactive Publication Date: 2020-06-16
NORTHWESTERN POLYTECHNICAL UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Although its dielectric properties are excellent and adjustable, due to the high brittleness and hardness of silicon nitride ceramics, the silicon nitride ceramic radome prepared by the general sintering process generally has low toughness, poor formability and difficult machining , comprehensive performance needs to be improved urgently, etc.
There is currently no information about Si 3 N 4f / Si 3 N 4 Research Report on Composite Radome

Method used

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  • Preparation method of high-temperature wave-transparent silicon nitride radome
  • Preparation method of high-temperature wave-transparent silicon nitride radome
  • Preparation method of high-temperature wave-transparent silicon nitride radome

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preparation example Construction

[0055] Step 4. Preparation of boron nitride interface and silicon nitride substrate

[0056] The degummed fiber preform is placed in a deposition furnace, and a layer of uniform boron nitride interface with a thickness of 500-800 nm is deposited on the silicon nitride fiber preform by CVI technology. Then, the silicon nitride substrate is prepared by the CVI process, and after 180-360 hours of deposition, the material is separated from the graphite mold (that is, demolded), and a semi-finished radome with a certain strength and high formability is obtained. Then, using the PIP process, the silicon nitride substrate is further prepared on the semi-finished product of the radome. After 2 to 5 dipping-cracking cycles, the porosity is 10-40%, and the density is 1.6-2.2g / cm 3 Si 3 N 4f / Si 3 N 4 Composite radome.

[0057] Preparation of anti-ablation nose cone for split radome

[0058] According to the structural requirements of the split radome, the silicon-based body of the...

Embodiment 1

[0071] Step 1. Graphite mold preparation. The specific process is:

[0072] Step 1.1 Design and prepare a graphite mold according to the size requirements of the silicon nitride radome and the requirements of a split or integrated structure.

[0073] Step 1.2 Place the graphite mold in a chemical vapor deposition furnace, and deposit a layer of silicon nitride coating with a thickness of 50-100 μm on the surface to prevent the carbon element from the surface of the mold from diffusing to the fiber preform, so as to ensure a good radome. Wave performance. The coating deposition process is as follows: silicon tetrachloride (SiCl 4 ), ammonia (NH 3 ) as the reaction source, hydrogen (H 2 ) to take out SiCl by bubbling 4 The carrier gas, argon (Ar) is the diluent gas, the deposition temperature is 1000-1200°C, the deposition pressure is 2-5kPa, and the deposition time is 50-100h.

[0074] Step 2. Weaving of silicon nitride fiber preform. The specific process is:

[0075] A...

Embodiment 2

[0088] Step 1. Graphite mold preparation. The specific process is:

[0089] Step 1.1 Design and prepare a graphite mold according to the size requirements of the silicon nitride radome and the requirements of a split or integrated structure.

[0090] Step 1.2 Place the graphite mold in a chemical vapor deposition furnace, and deposit a layer of silicon nitride coating with a thickness of 50-100 μm on the surface to prevent the carbon element from the surface of the mold from diffusing to the fiber preform, so as to ensure a good radome. Wave performance. The coating deposition process is as follows: silicon tetrachloride (SiCl 4 ), ammonia (NH 3 ) as the reaction source, hydrogen (H 2 ) to take out SiCl by bubbling 4 The carrier gas, argon (Ar) is the diluent gas, the deposition temperature is 1000-1200°C, the deposition pressure is 2-5kPa, and the deposition time is 50-100h.

[0091] Step 2. Weaving of silicon nitride fiber preform. The specific process is:

[0092] T...

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Abstract

The invention relates to a preparation method of a high-temperature wave-transparent silicon nitride radome. A framework structure is a prefabricated body formed by weaving silicon nitride fibers, a cover body is made of a silicon nitride fiber reinforced silicon nitride ceramic matrix composite material, a silicon nitride whisker reinforced silicon nitride coating is prepared on the surface, andthe radome has excellent strength and toughness and good high-temperature wave-transparent performance and machinability. According to the radome densification process, a CVI process and a PIP processare combined, and the content of silicon nitride matrixes prepared by different processes is reasonably regulated and controlled, so that composite materials with different densities, microstructuresand performances can be obtained, and different use requirements are met. The radome has two structural forms. The integrated structure is complete, and the mechanical property and broadband wave-transparent property of the radome are more excellent. A silicon nitride ceramic nose cone is added to the split structure, so that the radome has higher ablation resistance when serving in a severe environment.

Description

technical field [0001] The invention belongs to a method for preparing a radome, and relates to a method for preparing a high-temperature wave-transmitting silicon nitride radome. Background technique [0002] With the development of aircraft technology, modern battlefields have increasingly stringent requirements for electronic communication and electronic countermeasure technology. High-performance radome that can be used in harsher environments has always been a research hotspot in various countries. Silicon nitride ceramics (Si 3 N 4 ) The material has excellent mechanical properties, oxidation resistance, high temperature stability, chemical stability and moderate dielectric properties, and can exhibit good wave transparency on the basis of maintaining a certain porosity, so it becomes an excellent high temperature wave transparent material candidate. [0003] The currently published research on silicon nitride radome mainly includes the following contents: [0004]...

Claims

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Application Information

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IPC IPC(8): C04B35/591C04B35/80C04B35/81C04B35/622H01Q1/42
CPCC04B35/591C04B35/622H01Q1/42C04B2235/5244C04B2235/5276C04B2235/614C04B2235/616
Inventor 成来飞叶昉张立同周杰付志强崔雪峰
Owner NORTHWESTERN POLYTECHNICAL UNIV