Material extrusion 3D printing of large-scale SiC honeycomb metastructure for ultra-broadband and high temperature electromagnetic wave absorption

Electromagnetic (EM) wave absorbing materials have been widely used in various equipment to reduce the interference caused by EM waves. However, current EM wave absorbing materials are limited by narrow absorption bandwidth under high temperatures due to a lack of structural design. Herein, SiC ceramic and largescale SiC honeycomb metastructure were monolithically fabricated by material extrusion 3D printing. The real permittivity and imaginary permittivity of as-obtained SiC ceramic approached 10 and 2.3 within the frequency of 2 - 18 GHz. After optimized structure design, the as-obtained SiC honeycomb metastructure exhibited broadband EM performance of -10 dB effective bandwidth from 4.85 to 39.49 GHz (34.64 GHz) when the incident angle was 60 degrees at room temperature. Moreover, the as-obtained SiC honeycomb structure had a stable broadband -10 dB effective bandwidth of above 35 GHz when the incident angle is 60 degrees even after in-situ 1000 degrees C and exsitu 1600 degrees C erosion in the air atmosphere. Broadband EM wave absorption under oblique incident wave was also achieved from 30 degrees to 60 degrees both in transverse electric (TE) polarization and transverse magnetic (TM) polarization. This novel strategy unravels the potential of additive manufacturing of high -performance EM wave absorbers for high temperature environment applications.