Ni1−xZnxFe2O4/coal-based carbon composites with tunable electromagnetic wave absorption properties prepared with microwave irradiation and hydrothermal reaction

A simple hydrothermal method combined with microwave irradiation was used to synthesize nickel-zinc ferrite/coal-based carbon (Ni1−xZnxFe2O4/CBC) composites. The influences of Zn2+ concentration on the magnetism and microwave absorption characteristics of Ni1−xZnxFe2O4/coal-based carbon composites were examined. The Ni1−xZnxFe2O4 particles were equally anchored on the coal-based carbon within the Ni1−xZnxFe2O4/CBC composites. The dielectric and magnetism characteristics of Ni1−xZnxFe2O4/CBC composites can be improved simultaneously by adjusting the Zn2+ concentration. The minimum reflection loss (RLmin) for the sample at x = 0.4 is −65.5 dB for a thickness of 4.0 mm. The samples also have typical soft magnetic properties. Furthermore, some possible mechanisms of microwave absorption are investigated. Our Ni1−xZnxFe2O4/CBC composites show great potential for microwave absorption applications.