Enhanced microwave absorption properties of Ni decorated flaky graphite powders with frequency selective surfaces incorporation

Reasonable design of composition and structure is an effective way to improve microwave absorption performance of absorber. In this study, flaky Ni@Graphite composite powders containing various Ni contents were successfully fabricated through a facile electroless plating process. The phase compositions and microstructure of the composite powders were characterized. XRD and SEM results showed that the Ni particles are successfully reduced from the solution and anchored on the flaky Graphite. The electromagnetic and microwave absorption properties of the Ni@Graphite composite powders were also studied. The results illustrated that although the composite powders with 45 % Ni owned the minimum reflection loss (RL_min) of −18 dB, the maximum effective absorption bandwidth (EAB_max) was only 1.1 GHz for the sample with 2.0 mm thickness. So periodic frequency selective surfaces (FSS) were designed to further improve the microwave absorption performance. As the structural parameters of the FSS were C = 14 mm, T1 = 1.78 mm, e = 1.18 mm, R = 1.86 mm and a = 1.6 mm, the optimized RL_min and EAB_max of the Ni@Graphite powders were −19.27 dB and 3.2 GHz, respectively. It was worth noting that the strategy of balancing the electromagnetic properties of dual-loss composites by controlling the composition and structure can effectively improve microwave absorption performance. This work contributes to the development of high-performance Ni@Graphite microwave absorption materials.