Electromagnetic Wave Absorption Performance on Fe₃O₄ Polycrystalline Synthesized by the Synergy Reduction of Ethylene Glycol and Diethylene Glycol

Fe₃O₄ nanoparticles were synthesized by hydrothermal method with the synergy reduction of ethylene glycol (MEG) and diethylene glycol (DEG). The purity, grain size, magnetism, and the microwave absorption performance of the samples can be controlled by the concentration of DEG in the precursor solution. Under the optimized condition of synthesis, the product is a highly crystallized cubic Fe₃O₄ and the crystallite size of Fe₃O₄ is about 44-60 nm with the saturation magnetization of about 96 emu/g. The Fe₃O₄ paraffin composites exhibit excellent microwave absorption properties at the frequency range of 1-18 GHz, which are attributed to the electron transition resonance, natural resonance, and polarization of Fe₃O₄. The minimum reflection loss of Fe₃O₄ synthesized under the MEG and DEG content of 3.58 and 2.10 mol/L, respectively, can reach -42 dB at a thickness of 2.1 mm. And the effective absorption bandwidth of the samples can reach 3.9 GHz (7.3-11.2 GHz) at a thickness of 2.5 mm. The result demonstrates that Fe₃O₄ nanoparticles synthesized with DEG as auxiliary reducing agent and surfactant have a good microwave absorption performance.