GR-Fe3O4@C/PLA 3D printed composites for broadband microwave absorption

Both magnetic and dielectric materials play crucial roles in the field of microwave absorption and are highly favored by researchers. Fe3O4 is a typical magnetic dielectric material characterized by high magnetic saturation strength. Graphene (GR), as a dielectric material, is known for its low density, high specific surface area, and excellent electrical conductivity. 3D printing technology, with its advantages of high design flexibility and low cost, holds significant promise in the field of microwave absorption. This paper utilizes these characteristics to prepare Fe3O4@C core-shell structural composites through a solvent evaporation method and high-temperature carbonization process. Subsequently, physical mixing and high-temperature extrusion are employed to fabricate GR-Fe3O4@C/PLA composites. The study investigates the impact of Fe3O4, core-shell structure, and graphene content on the microwave absorption performance of these composites. Additionally, the electromagnetic loss mechanism is comprehensively analyzed. Experimental findings indicate that the composites achieve optimal microwave absorption performance with a graphene content of 4 wt% (GR- Fe3O4@C/PLA-4). At a thickness of 2 mm, the material demonstrates a minimum reflection loss (RLmin) of -33.16 dB at 15.36 GHz, accompanied by an effective absorption bandwidth (EAB) of 4.8 GHz (ranging from 13.2 GHz to 18 GHz). Moreover, at a sample thickness of 2.5 mm, the effective absorption bandwidth expands to 6.4 GHz (ranging from 8.48 GHz to 14.88 GHz). These experimental results underscore the potential of these composites in microwave absorption applications, particularly in environments requiring broadband microwave absorption capabilities.