Microwave absorbing ceramic of silicon carbide compound material and preparation method thereof

Abstract

The invention discloses microwave absorbing ceramic of a silicon carbide compound material and a preparation method thereof. The microwave absorbing ceramic has a multifunctional layer laminated structure which comprises a matching layer, a depletion layer, a dielectric layer and a reflecting layer, wherein the matching layer, the depletion layer and the dielectric layer are respectively made of a continuous silicon carbide fiber reinforced silicon carbide-based compound material; the reflecting layer is made of a continuous carbon fiber reinforced silicon carbide-based compound material; andcontinuous silicon carbide fiber and continuous carbon fiber have different electrical resistivity. The preparation method comprises the flowing steps of: selecting a reinforced material; preparing asizing agent; preparing a rough blank; and preparing a finished product. The microwave absorbing ceramic has a wider absorbing frequency band, a higher mechanical property and a heat-resistant function.

Description

technical field [0001] The invention mainly relates to the field of radar wave-absorbing ceramics, in particular to a wave-absorbing ceramic made of silicon carbide composite 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, and are 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 tempera...

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Problems solved by technology

[0002] The radar absorbing ceramic materials currently developed are mainly made of ceramic micropowder as the radar absorber, and are 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 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) composites and continuous carbon fiber reinforced silicon carbide (C f / SiC) composite materials are mainly used for thermal protection and thermal structure. Because the necessary dielectric properties have not been modified, the radar absorbing performance is not ideal.

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