Abstract: Exfoliated graphite was separated into nanosized flakes by ultrasonication and acid treatment, and then FeCoNi alloy particles were deposited uniformly on the surface of flakes by codeposition method and annealing treatment process. Magnetic and microwave absorbing properties of the obtained samples were measured. The results show that the synthesized composites possess good soft magnetic performance and effective microwave absorption. The composite consisting of Fe₃Co₆Ni/graphite flakes annealed at 600℃ as an absorber has the maximum absorption value of -24dB at 12.6GHz, and the effective absorbing bandwidth (<-5dB) is about 8GHz. The characteristics of microwave absorption can be controlled by adjusting element ratios in alloy and the parameters of heat treatment process. This kind of composite has great potential and investigation value in microwave absorbing fields.

Key words: graphite flakes, FeCoNi alloy, microwave absorbing materials