Absorption-dominant microwave shielding properties of Sn0.2Fe2.8O4-graphite-PVDF ternary nanocomposite films. (24th November 2021) - P, Lavanya Rathi
Abstract: Absorption-dominant microwave shields are in high demand for mitigating the effect of electromagnetic interference (EMI) on devices and the environment. In this paper, we describe the development of absorption enhanced ternary nanocomposites and their EMI shielding capability. Polymer based shields have been fabricated by dispersing conducting graphite and magnetic spinel ferrite Sn0.2 Fe2.8 O4 nanoparticles in electroactive polymer polyvinylidene fluoride. Shielding effectiveness (SE) values in the expected range of 10–30 dB in the X-band region, were achieved with as low as 30–50 wt% of pristine graphite and 1–10 wt% of Sn0.2 Fe2.8 O4 . The industrial standard of 99% shielding (SE ⩾ 20 dB) was obtained with 50 wt% of graphite. The composites exhibit absorption as the dominant mechanism of shielding. The percentage SE due to absorption is about 70% and is tuned upwards by the increase in ferrite concentration. The composites were characterized by x-ray diffraction and vibrating sample magnetometry; thermal analysis confirms their stability. The thin, flexible films fabricated by the simple and cost-efficient technique of solution casting will be extremely valuable as wrap-on shields for X-band microwave attenuation.