Synthesis and enhanced microwave absorption properties of BaM-P/BaM-T/PVB ternary composite with ordered inter-filled structure

The granular ferrite fillers like BaFe₁₂O₁₉ (BaM-P) usually work as an auxiliary material in the EMA composite, but shows weak electromagnetic wave absorbing (EMA) capability (RL > − 10 dB) when single used. In this work, an orderly filled ferrite/polymer composite has been made by a versatile tape casting method. The micron BaFe₁₂O₁₉ template particles (BaM-T) were obtained by a two-step molten salt method and were oriented and uniformly inserted into the BaM-P/polyvinyl butyral (PVB) composite to form a BaM-T/BaM-P/PVB ternary composite with laminated micro-structure. The composite shows greatly enhanced EMA properties with broadening effective EMA bandwidth. The optimal sample displayed a minimum reflection loss of − 45.8 dB at 6.6 GHz and effective EMA bandwidth (RL < − 10 dB) of 3–18 GHz with 2–5 mm thick. The maximum effective EMA bandwidth of 4.16 GHz was obtained at the thickness of 1.8 mm. Finite element simulation verified that, the strong barrier interfaces attributed by the oriented BaM-T flakes can effectively improve absorptive intensity and decrease sample thickness via a particular multiple reflection mechanism. Additionally, the large range of filler particle size from nano to micro can make the effective bandwidth to be broadened. This work demonstrates the great potential of the ferrite materials for EMA application.