Heat-resistant wave-absorbing material and preparation method thereof

Abstract

The invention discloses a heat-resistant wave-absorbing material, which is a composite material with quartz as matrix and a quartz fiber needled part as a reinforced phase. The composite material contains a short carbon fiber; the length of the short carbon fiber is 5-6mm; the volume content of the short carbon fiber in the composite material is 0.002-0.005g / cm<3>; the volume density of the quartz fiber needled part is 0.43-0.45g / cm<3>; and the preparation method disclosed by the invention comprises the following steps: selecting raw materials; preparing a fiber preformed part; dipping the fiber preformed part for a plurality of times; and carrying out gel and heat treatment until densification is finished. When the heat-resistant wave-absorbing material disclosed by the invention is 3.5mm in thickness, the reflectivity within a frequency range of 8-18GHz can be lower than -8dB; the heat-resistant wave-absorbing material has relatively good wave-absorbing property when the thickness is relatively small; and the preparation method disclosed by the invention is simple in processing step, free of a harmful and toxic pollutant in the technological process, and good in compatibility with the environment.

Description

technical field [0001] The invention belongs to the field of radar wave-absorbing materials, and in particular relates to a high-temperature-resistant wave-absorbing material and a preparation method thereof. Background technique [0002] There are two main types of radar absorbing ceramic materials currently developed. One is a particle-reinforced ceramic material that uses ceramic particles as a radar absorber and is prepared by a hot-pressing process, such as Si / C / N ceramic particle-reinforced LAS glass, mullite, Si 3 N 4 and other ceramic materials, but these materials have the following disadvantages: 1) Dielectric properties are difficult to achieve gradient distribution, and the radar absorption frequency band is narrow; 2) Particle-reinforced ceramic materials have poor toughness and are prone to catastrophic failure; 3) Hot pressing process is difficult Preparation of large complex components. The other is continuous fiber-reinforced ceramic matrix composites. Th...

AI Technical Summary

Problems solved by technology

One is a particle-reinforced ceramic material that uses ceramic particles as a radar absorber and is prepared by a hot-pressing process, such as Si / C / N ceramic particle-reinforced LAS glass, mullite, Si 3 N 4 and other ceramic materials, but these materials have the following disadvantages: 1) Dielectric properties are difficult to achieve gradient distribution, and the radar absorption frequency band is narrow; 2) Particle-reinforced ceramic materials have poor toughness and are prone to catastrophic failure; 3) Hot pressing process is difficult Preparation of large and complex components

[0004] The two radar absorbing ceramics disclosed above have excellent wave-absorbing characteristics, but there are still the following deficiencies: 1) the use of silicon carbide fiber reinforced silicon carbide composite material, the cost is relatively high; 2) special treatment of silicon carbide fiber is required In order to obtain the desired electrical properties, the process is complicated; 3) all adopt multi-layer structure, and the control of process parameters is relatively difficult; 4) the structure of two-dimensional composite materials is adopted, there is no fiber reinforcement between layers, and the interlayer strength is not ideal; 5) two-dimensional composite materials are used It is difficult to prepare components in the form of three-dimensional composite materials

[0005] The Chinese patent document with the patent number ZL 201210139046.2 proposes a method for preparing a three-dimensional quartz fiber-reinforced quartz wave-absorbing material using silicon carbide micropowder as an absorbent to solve some of the above problems, but the prepared wave-absorbing material has a narrow absorbing frequency band. insufficient

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