Preparation of Ce2Fe17N3–δ@FePO4 composite with excellent microwave absorption performance by reduction-diffusion (R/D) and phosphating processes

Ce2Fe17N3–δ composites have always been focused on electromagnetic wave (EMW) absorbing field because of their high resonance frequency and magnetic loss. However, the issues of preparation cost and impedance mismatching still limit the industrial conversion and practical application of Ce2Fe17N3–δ composites. In this work, the composites of Ce2Fe17N3–δ with a phosphate insulation layer (Ce2Fe17N3–δ@FePO4) were prepared by a newly-developed reduction-diffusion (R/D) and phosphating processes using CeO2 as raw materials, and their microwave absorption properties were investigated. The composite filled with 30 vol% of the Ce2Fe17N3–δ@FePO4 has a minimum reflection loss (RL) of −63 dB and an effective absorption bandwidth (EBW, RL < −10 dB) of 3.83 GHz at a thickness of 1.25 mm in the X-band, and the EBW reaches 5 GHz under 0.98 mm in the Ku-band. This study demonstrates that the Ce2Fe17N3–δ@FePO4 composites with low cost and excellent microwave absorption properties have a significant potential for industrial production and practical applications.