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

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 (BaFe ₁₂ O ₁₉ ) powder is first prepared using a microwave-assisted hydrothermal method, and then BaFe ₁₂ O ₁₉ /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 BaFe ₁₂ O ₁₉ /PPy/PVDF film is prepared using a casting molding process; then polyvinyl alcohol is used as a binder to prepare BaFe ₁₂ O ₁₉ /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 BaFe ₁₂ O ₁₉ magnetic metal, the intense dielectric loss of PPy, and the superior impedance matching result in excellent microwave absorption capability. The results show that the BaFe ₁₂ O ₁₉ /PPy/PVDF film or fabric is a promising and efficient microwave-absorbing material, being thin and strongly absorbing across a wide bandwidth.