Wave-absorbing ceramic made of silicon carbide composite material and preparation method thereof

Abstract

The invention discloses a wave-absorbing ceramic made of a silicon carbide composite material and a preparation method thereof. The wave-absorbing ceramic has a multifunctional superimposed structure comprising a matching layer, a consuming layer and a reflecting layer, wherein each functional layer is made of a continuous silicon carbide fiber reinforced silicon carbide-based composite material;and continuous silicon carbide fibers serving as a reinforced material of each functional layer have different resistivity. The preparation method for the wave-absorbing ceramic comprises the following steps of: selecting continuous silicon carbide fiber plain cloth; dipping and cracking the plain cloth of the consuming layer; mixing with polycarbosilane, divinylbenzene, dimethylbenzene and the like to prepare slurry; performing mould pressing, thermal crosslinking and cracking to prepare a wave-absorbing ceramic rough blank; and preparing the wave-absorbing ceramic made of the silicon carbide composite material by adopting a precursor dipping and cracking process. The wave-absorbing ceramic has wide absorption frequency band, high mechanical property and heatproof function.

Description

technical field [0001] The invention belongs to the field of radar wave-absorbing ceramics, and in particular relates to a radar wave-absorbing material with a multilayer structure and a preparation method thereof. Background technique [0002] The radar absorbing ceramic materials currently developed are mainly made of ceramic micropowder as the radar absorber, which is prepared by 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 It is difficult to prepare large and complex components. Continuous fiber reinforced ceramic matrix composites have the advantages of high temperature resistance, oxidation res...

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Problems solved by technology

[0002] The radar absorbing ceramic materials currently developed are mainly made of ceramic powder as a radar absorber, which is prepared by hot pressing technology, 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 Difficult to prepare large and complex components

Continuous fiber reinforced ceramic matrix composites have the advantages of high temperature resistance, oxidation resistance, high specific strength, high specific modulus, high toughness, etc., and are easy to form large and complex components, but the continuous silicon carbide fiber reinforced silicon carbide (SiC f / SiC) composite materials are mainly used for thermal protection and thermal structure. Due to the lack of necessary dielectric properties modification, the radar absorbing performance is poor

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