The different graphite morphologies, like graphite intercalation compound (GIC), expanded graphite (EG), and exfoliated graphite (ExfG), were investigated as microwave absorbing materials (MAMs). The modification of the GIC was carried out in two independent parts, consisting of heat treatment and subsequent ultrasound agitation, forming the EG and ExfG, respectively. The surface morphology and structural characterization were investigated using the scanning electron microscope and Raman spectroscopy. Electromagnetic characterization was performed with a vector network analyzer and rectangular waveguide in the frequency range from 8.2 to 12.4 GHz (X-band) and from 12.4 to 18 GHz (Ku-band). The effects of different graphite morphologies and thickness of the composite were analyzed on the electromagnetic properties. The results of the reflection loss show that the samples affect the performance of the MAMs. The EG sample presents an excellent attenuation of around − 22.5 dB (≈ 99 microwave attenuation) for 2 mm thickness samples within the X-band frequency range. This behavior can be attributed to the expanded and interconnected structure of the EG, which has a large surface area and connectivity between the structures within the composite. Thus, it was found that EG is the best graphite structure for application in microwave absorber of broadband. The GIC and ExfG exhibited poor performance of microwave absorption (above − 10 dB).

研究了石墨的不同形态，如石墨插层化合物（GIC），膨胀石墨（EG）和片状石墨（ExfG），作为微波吸收材料（MAM）。GIC的修改分为两个独立的部分，包括热处理和随后的超声搅拌，分别形成了EG和ExfG。使用扫描电子显微镜和拉曼光谱研究了表面形态和结构表征。用矢量网络分析仪和矩形波导在8.2至12.4 GHz（X波段）和12.4至18 GHz（Ku波段）的频率范围内进行电磁表征。分析了不同石墨形态和复合材料厚度对电磁性能的影响。反射损失的结果表明，样品会影响MAM的性能。对于X波段频率范围内2毫米厚的样品，EG样品呈现出出色的衰减-22.5 dB（≈99微波衰减）。此行为可归因于EG的扩展且相互连接的结构，该结构具有较大的表面积以及复合材料内部结构之间的连通性。因此，发现EG是用于宽带微波吸收器的最佳石墨结构。GIC和ExfG表现出不良的微波吸收性能（高于-10 dB）。此行为可归因于EG的扩展且相互连接的结构，该结构具有较大的表面积以及复合材料内部结构之间的连通性。因此，发现EG是用于宽带微波吸收器的最佳石墨结构。GIC和ExfG表现出不良的微波吸收性能（高于-10 dB）。此行为可归因于EG的扩展且相互连接的结构，该结构具有较大的表面积以及复合材料内部结构之间的连通性。因此，发现EG是用于宽带微波吸收器的最佳石墨结构。GIC和ExfG表现出不良的微波吸收性能（高于-10 dB）。