Preparation and microwave absorbing property of porous FeNi powders

•Porous FeNi powders were prepared by a precipitation-thermal decomposition procedure.•Excellent microwave absorbing property was obtained for the FeNi powder.•Porous structure is available for an enhanced microwave absorbing property.

Porous FeNi powders with particle size of 1 μm were successfully prepared by two steps in this paper. First, Fe0.5Ni0.5C2O4·2H2O particles with uniform size distribution and morphology were obtained by an oxalate precipitation process. Second, the porous FeNi powders were prepared by thermal decomposition of the oxalate precursor at 450 °C for 30 min in a N2/H2 mixed atmosphere. The electromagnetic (EM) parameters of FeNi (30 wt%)/paraffin composite were measured in 2-18G Hz, and the reflection loss (RL) values were calculated based on the transmission line theory. The results show that the bandwidth of RL < −10 dB reaches 2.57G Hz when the composite thickness is 2.0 mm, and the minimum RL reaches −52.58 dB at 6.82G Hz with a composite thickness of 3 mm.

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