Graphene nanosheets (GNSs)/ZnO/Al₂O₃ composite coatings with different GNSs content were prepared by air plasma spraying technique. The scanning electron microscope results show that the GNSs were homogeneously dispersed in the powders and coatings. The influence of different GNSs content on complex permittivity and microwave absorption properties have been systematically investigated at the frequency range from 8.2 to 12.4 GHz. The complex permittivity of the coating was improved with the increase in GNS content, due to the high conductivity and polarization loss of GNS. The GNSs/ZnO/Al₂O₃ coating with 15 wt.% GNSs in the thickness of 1.82 mm presented the most prominent microwave absorption properties, which exhibited strong absorption (minimum reflection loss of −45 dB) and the reflection loss ≤ −10 dB bandwidth at the frequency range of 11.2-12.0 GHz. Meanwhile, the hardness of the coating increased from 914.2 HV_0.2 to 1057.3 HV_0.2 with the introduced 15 wt.% GNSs. These results suggest that GNS can be a promising nanofiller to simultaneously improve the microwave absorption properties and mechanical properties of absorbing coatings.

采用空气等离子喷涂技术制备了不同GNSs含量的石墨烯纳米片(GNSs)/ZnO/Al ₂ O ₃复合涂层。扫描电子显微镜结果表明，GNSs 均匀分散在粉末和涂层中。已在 8.2 至 12.4 GHz 的频率范围内系统地研究了不同 GNS 含量对复介电常数和微波吸收特性的影响。由于 GNS 的高电导率和极化损失，涂层的复介电常数随着 GNS 含量的增加而提高。GNSs/ZnO/Al ₂ O ₃厚度为 1.82 mm 的含 15 wt.% GNS 的涂层表现出最突出的微波吸收特性，在 11.2- 频率范围内表现出强吸收（最小反射损耗为 -45 dB）和反射损耗≤ -10 dB 带宽12.0 GHz。同时，涂层的硬度从 914.2 HV _0.2增加到 1057.3 HV _0.2，引入 15 wt.% GNSs。这些结果表明，GNS 是一种很有前途的纳米填料，可以同时改善吸收涂层的微波吸收性能和机械性能。