The Research On Synthesis And Microwave Absorption Property Of FeCo/Graphite Nanocomposites

Microwave absorbing material is a new kind of functional material. It could transform the energy of microwave into some other forms, which aims to reduce the microwave reflection. The development of modern technology needs more efficient microwave absorbing material. Transition metals and their alloys is a kind of frequently used microwave absorbing material. It could combine the advantage of the two kinds of materials if we use graphite and transition metals to produce nanocomposites. The research of the nanocomposites on microwave absorption may greatly advance the development of microwave absorbing material.Firstly, we used intercalation reaction to insert FeCl₃, CoCl₂ into graphite layers, and then synthesised the FeCo/graphite nanocomposites by reducing the presoma with H₂. The crystal structure, Morphology and electromagnetic properties were characterized by XRD,SEM and electromagnetic parameter measurement. The influence of the time and temperature of the reduction to its morphology were also investigated. The result shows that the sample was mainly composed of FeCo alloy and graphite. The FeCl₃, CoCl₂ in the sample could not be reduced completely. With the increase of the time and temperature of the reduction, the content of FeCl₃, CoGl2 decreased. The properly set content of binder and FeCo alloy could improve the sample's theoretic reflection losses.Secondly, The FeCo/Graphite nanocomposites were prepared by the absorption of the Fe³⁺ and Co²⁺ into layers of the graphite oxide and the reduction of the Fe³⁺Co²⁺/graphite oxide compounds with H₂. The Morphology, crystal structure and magnetic properties were characterized by XRD, SEM and Magnetic loop analysis, and the influence of the content of FeCo alloy on the microwave absorption properties were also investigated. The results indicated that the composites were composed of graphite and FeCo alloy. The diameters of the nano particles on and inside the graphite layers ranged from 30nm to 150nm. The FeCo/Graphite nanocomposites are typical soft magnetic materials. The saturation magnetization decreases with the decrease of the content of the FeCo alloy. Stronger dielectric loss and weaker magnetic loss could be detected when the content of FeCo alloy decreases. The frequency which the peaks of theoretic reflection loss located moved to the lower frequency band.