Flexible fabrics based on BaFe 12 O 19 /PPy/PVDF composite filler for enhancing microwave absorption bandwidth and strength

Abstract

Magnetic–dielectric composites are an effective strategy for developing efficient microwave absorbers, owing to the synergistic effect of different attenuation mechanisms. In this work, barium ferrite (BaFe₁₂O₁₉) powder is first prepared using a microwave-assisted hydrothermal method, and then BaFe₁₂O₁₉/polypyrrole (PPy) composite powders with different contents of PPy were prepared using an in situ polymerization method. Polyvinylidene difluoride (PVDF) is selected as the film-forming agent, and BaFe₁₂O₁₉/PPy/PVDF film is prepared using a casting molding process; then polyvinyl alcohol is used as a binder to prepare BaFe₁₂O₁₉/PPy/PVDF film or fabric with a strong microwave absorption performance. The minimum reflection loss (RL_min) is as high as −36.52 dB at 16.31 GHz for a thickness of 2.5 mm. The adequate absorption bandwidth (RL ≤ −10 dB) is as wide as 7.98 GHz for the same thickness, covering almost all X and K_u bands. The absorption mechanism is revealed in detail through an in-depth analysis of the electromagnetic parameters. The synergistic effect of the solid magnetic loss of BaFe₁₂O₁₉ magnetic metal, the intense dielectric loss of PPy, and the superior impedance matching result in excellent microwave absorption capability. The results show that the BaFe₁₂O₁₉/PPy/PVDF film or fabric is a promising and efficient microwave-absorbing material, being thin and strongly absorbing across a wide bandwidth.