Preparation and Microwave Absorbing Properties of FexNi1-x Alloy Powders

The FexNi1-x(0<1) alloy powders with different compositions were prepared by an oxalate precipitation-precursor thermal decomposition process. The phase structure and morphology of the precursor and Fe.,Ni, powder were characterized by XRD and SEM, respectively. With the increase of Ni content, the phase structure of precursor was gradually changed from FeC(2)o(4) . 2H(2)O to NiC2O4 . 2H(2)O, and the morphology was changed from short rod to cube and polyhedron. The Fe.,Ni, powders show porous structure and its geometric shape is similar to the corresponding precursor and the particle size becomes smaller. The phase structure of Fe.,Ni, powders is changed with the composition from iron-rich bcc to nickel-rich fcc structure. The electromagnetic parameters of the composites of Fe.,Ni, powders and paraffin were measured and the microwave absorbing properties were calculated. The results reveal that Feo.,Ni, sample shows a best electromagnetic loss, and when the composite thickness is 3. 0mm, the minimum RL reaches 52. 58dB at 6. 82GHz. Fe-0.6 Ni-0.4 sample with a thickness of 1. 5mm shows a maximum effective bandwidth (RL<-10dB), which reaches up to 4. 02GHz.