Synthesis and microwave absorbing properties of FeCo alloy particles/graphite nanoflake composites

Exfoliated graphite was processed into nano-sized flakes by jet milling, ultrasonication and acid treatments, and then FeCo alloy particles were uniformly deposited onto the surface of the prepared graphite nanoflakes (GNFs) by a co-deposition and subsequent annealing process in reducing atmosphere. The FeCo-GNFs composites demonstrate good soft magnetic performance and effective microwave absorption, especially in the lower frequency range. The strongest absorption reaches -30.6 dB at 7.4 GHz with a coating thickness of 2 mm. Furthermore, effective microwave absorption at different frequency bands can be acquired by adjusting the coating thicknesses and filling ratios of FeCo-GNFs absorber. Considering the low cost and high efficiency, the FeCo-GNFs composites have great potential as microwave absorber for practical applications. (C) 2010 Elsevier B.V. All rights reserved.