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BN (Boron nitride)-modified SiO2 composite material and preparation method thereof

A composite material and modification technology, which is applied in the field of material processing, can solve the problems of brittle failure of composite materials, lack of reinforcement and toughening of quartz fibers, high preparation temperature, etc., and achieve good moisture absorption ability, short cycle and simple preparation process Effect

Inactive Publication Date: 2018-06-22
JIANGXI JIAJIEXINDA NEW MATERIAL TECH CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Qi Gongjin and Zhang Changrui from the National University of Defense Technology prepared 2.5D SiO by pyrolysis of silicon nitride precursor combined with silica sol impregnation and sintering 2f / SiO 2 – Si 3 N 4 Composite material with a density of 1.64g / cm 3 increased to 1.79g / cm 3 , the bending strength increased to 95.9MPa, but due to the infiltration of silicon nitride, and the preparation temperature of the precursor pyrolysis method was too high, the interfacial bonding between the fiber and the matrix was strong, and the composite material showed brittle failure characteristics
[0006] But for SiO 2f / SiO 2 The research on materials has only a few decades of history, and there are still many problems to be solved from the perspective of material preparation: 1. Crystallization behavior of quartz glass
The strong combination of quartz fiber and quartz glass matrix makes the material show obvious brittle fracture when fractured, and does not play the role of strengthening and toughening of quartz fiber

Method used

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  • BN (Boron nitride)-modified SiO2 composite material and preparation method thereof

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0024] Example 1 A kind of SiO modified with BN coating for radome and antenna window is proposed 2f / SiO 2 composite materials such as figure 1 As shown, its preparation method comprises the following steps:

[0025] (1) First, the 2D SiO 2f The preform was soaked in absolute ethanol for 22h, then placed at room temperature for 74h, then placed in a muffle furnace, heated to 550°C at a heating rate of 450°C / h, kept for 3 hours, and then cooled to room temperature.

[0026] (2) Dissolve boric acid and urea with a mass ratio of 1:2.5 in a mixed solution of ethanol and water with a volume ratio of 2:1, and stir to dissolve completely until the solution is clear and transparent, and then adjust the pH of the solution to 7.0.

[0027] (3) SiO treated in step (1) 2f The preform is put into the impregnation tank, and the solution obtained in step (2) is injected, then vacuumized and maintained for 0.3h, and then the protective gas is introduced to 1.103×10 5 Pa and maintained ...

Embodiment 2

[0035] Example 2 A kind of SiO modified with BN coating for radome and antenna window is proposed 2f / SiO 2 The composite material, its preparation method comprises the steps:

[0036] (1) First, 2.5D SiO 2f The preform was soaked in absolute ethanol for 26h, then placed at room temperature for 70h, then placed in a muffle furnace, heated to 450°C at a heating rate of 550°C / h, kept for 5h, and then cooled to room temperature.

[0037] (2) Dissolve boric acid and urea with a mass ratio of 1:1.5 in a mixed solution of ethanol and water with a volume ratio of 4:1, and stir to dissolve completely until the solution is clear and transparent, and then adjust the pH of the solution to 5.0.

[0038] (3) SiO treated in step (1) 2f The preform is put into the impregnation tank, and the solution obtained in step (2) is injected, then vacuumized and maintained for 0.8h, and then the protective gas is introduced to 8.104×10 4 Pa and maintained pressure for 0.8h, then taken out and dri...

Embodiment 3

[0046] Example 3 A kind of SiO modified with BN coating for radome and antenna window is proposed 2f / SiO 2 The composite material, its preparation method comprises the steps:

[0047] (1) First, the 3D SiO 2f The preform was soaked in absolute ethanol for 24 hours, then placed at room temperature for 72 hours, then placed in a muffle furnace, heated to 500°C at a heating rate of 500°C / h, kept for 4 hours, and then cooled to room temperature.

[0048] (2) Dissolve boric acid and urea with a mass ratio of 1:2 in a mixed solution of ethanol and water with a volume ratio of 3:1, and stir to dissolve them completely until the solution is clear and transparent, and then adjust the pH of the solution to 6.0.

[0049] (3) SiO treated in step (1) 2f The preform is put into the impregnation tank, and the solution obtained in step (2) is injected, then vacuumized and maintained for 0.5h, and then the protective gas is introduced to 9.927×10 4 Pa and maintained pressure for 0.5h, th...

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Abstract

The invention relates to a BN (Boron nitride) coating modified SiO2f / SiO2 composite material for a radar dome and an antenna window and a preparation method thereof. The method comprises the followingsteps: surface pre-treatment, preparation of a BN coating precursor, dipping of a BN coating, thermal treatment of the BN coating, dipping of preforms, sintering of preforms, density measurement andmaterial grinding. The preparation process disclosed by the invention is simple, a period is short, the density of a material can reach 1.8g / cm<3>, the bending strength can reach 120MPa, a dielectricconstant is less than or equal to 3, dielectric loss under frequency of 2GPa to 18GPa is not more than 0.02, the working can be continuously carried out for 10 minutes at a high temperature of 800 DEGC, and an instantaneous working temperature can reach 1200 DEG C. The BN-modified SiO2f / SiO2 composite material and the preparation method disclosed by the invention have the advantages that the moisture absorption prevention ability is good, the problem that the characteristics including easiness for crystallization, low densification degree and mechanical strength of an existing SiO2f / SiO2 composite material cannot meet a use requirement is solved, and the density and mechanical performance of the material are improved.

Description

technical field [0001] The invention belongs to the technical field of material processing, and in particular relates to a SiO modified with BN coating for a radar radome and an antenna window 2f / SiO 2 Composite materials and methods of making the same. Background technique [0002] The radome is an important part of the front end of the homing guided missile. It is a barrier to protect the antenna system from the harsh aerodynamic environment caused by high-speed flight and to carry out normal signal transmission work. With the development of aerospace technology, the current flight speed of various advanced tactical missiles is more than 4Ma, and the reentry speed of surface-to-surface missiles has reached 8Ma ~ 12Ma, or even higher, which makes the missile radome face more and more severe challenges. test. [0003] The early radome material is a monolithic or sandwich structure using glass fiber reinforced plastic, but the heat resistance of plastic is poor, and it c...

Claims

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Application Information

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IPC IPC(8): C04B35/14C04B35/64C04B41/85
CPCC04B35/14C04B35/64C04B41/009C04B41/5064C04B41/85C04B2235/3409C04B2235/46C04B2235/465C04B2235/6562C04B2235/77C04B2235/96C04B41/4558
Inventor 吴宝林侯振华
Owner JIANGXI JIAJIEXINDA NEW MATERIAL TECH CO LTD
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