Electromagnetic wave absorbing properties of flexible thermal conductive ZnO@FeSiAl silicone rubber

Abstract

Thermal conductive and microwave absorbing materials are important for addressing electromagnetic radiation and heat accumulation in electronic devices. In this study, ZnO@FeSiAl composite powders with different morphologies were synthesized using three routes. These powders were added to silicone rubber to prepare thermal conductive and microwave absorbing composites. The study explores the effect of different morphologies of ZnO@FeSiAl on the wave-absorbing performance of silicone rubber. XRD confirmed the successful synthesis of ZnO powders. SEM revealed that ZnO particles were uniformly distributed on the FeSiAl surface. The mixed ZnO@FeSiAl silicone rubber had the highest tensile strength and elongation, with a tensile strength of 3.67 MPa and an elongation at a break of 40.75 %. The network shaped ZnO@FeSiAl silicone rubber had the highest thermal conductivity and electromagnetic parameters, with a thermal conductivity of 1.65 W/(m·K). The synergetic effect between ZnO and FeSiAl achieved a minimum reflection loss (RL_min) of −71.38 dB at 8.23 GHz for the composite with a thickness of 2.8 mm. The effective absorption bandwidth (EAB) covered the entire X-band. The introduction of a frequency selective surface (FSS) shifted the absorption peak of the silicone rubber to a lower frequency, moving significantly from 12.08 GHz to 8.47 GHz. This work helps to address the problems of heat accumulation and electromagnetic pollution in electronic devices.