Versatile closed-cell SiC/C foam for microwave absorption under medium temperature, icing and mechanical conditions

Microwave-absorbing materials (MAMs) for applications such as aircraft protective layers and ship side panels often need to take into account the actual working conditions. Conventional MAMs are often difficult to take into account special functional requirements such as mechanics, high temperature, de-icing, etc. Therefore, there is an urgent need to develop MAMs with harsh environmental adaptability and multifunctional requirements. Here, we utilize SiO2 microspheres and phenolic resin to prepare precursor foams, and through calcination, we have prepared closed-cell SiC/C foam composites with both microwave absorption properties, mechanical properties and thermal properties. The effective absorption bandwidth (EAB) of the samples is up to 6.9 GHz at a thickness of 7.3 mm, which can satisfy the perfect coverage of the C-band, and can be further broadened by structural design. The samples can satisfy the full coverage of the X-band at 200 °C. The samples have loaded properties, and the maximum compressive strength of the samples is up to 10.5 mm. The samples are loaded with a maximum compression strength of 8 MPa, support repeated medium-temperature heating, and maintain a compression performance of 5.7 MPa after heating. The samples have good thermal conductivity and Joule thermal properties, and the surface temperature can be rapidly increased under the condition of applying a heat source or applying a low pressure to cope with the cold and humid working conditions. The composites in this paper are simple to prepare and have the potential for mass production.