Preparation and microwave properties of lamellar Fe/BaFeO_2.5 composite particles with hydrogen-thermal reduction method

Fe/BaFeO_2.5 laminated composite particles were successfully prepared by hydrogen-thermal reducing BaFe₁₂O₁₉ particles. The average diameter of Fe/BaFeO_2.5 composite particles is about 1 μm and the lamellar thickness is about 100 nm. The effective permittivity and permeability of Fe/BaFeO_2.5 laminated composite particles were measured and EMA performance was evaluated. Compared with Fe particles with a similar diameter, the permeability of Fe/BaFeO_2.5 composite particles is remarkably improved by the induction of insulator BaFeO_2.5 phase. Due to the unique 2-dimension shape characteristic, ε' and μ' of Fe/BaFeO_2.5 laminated composite particles is obviously higher than that of Fe/BaFeO_2.5 composite particles without lamellar structure. EMA performance of coating containing Fe/BaFeO_2.5 laminated composite particles as fillers is excellent, and a maximum reflection loss (RL_max) up to -29.94 dB was achieved in a coating of 1.36 mm. Meanwhile, the operation frequency band of coating containing Fe/BaFeO_2.5 laminated composite particles as fillers covers completely X-band and Ku-band, which considerably wider than most of reported EMA coatings.