Hydrothermally synthesized Zn ferrite/multi-walled carbon nanotubes composite with enhanced electromagnetic-wave absorption performance

Zn ferrite/multi-walled carbon nanotubes (Zn ferrite/MWCNTs) composite were prepared by one-pot hydrothermal method. Their crystal structure, morphology, composition, magnetic properties, and electromagnetic-wave (EM-wave) absorption performance were measured by X-ray powder diffraction, field-emission scanning electron microscopy, high-resolution transmission electron microscopy, X-ray photoelectron spectroscopy, vibrating sample magnetometry, and vector network analysis. Results indicated that Zn ferrite particles were distributed on MWCNTs surface with agglomeration, and MWCNTs crucially affected the magnetic properties of Zn ferrite/MWCNTs composite. Compared with Zn ferrite, Zn ferrite/MWCNTs composite showed low addition amount, low coating thickness, and enhanced EM-wave absorption performance. With 60 wt% addition amount and 1.5 mm coating thickness, the minimum reflection loss of Zn ferrite/MWCNTs composite was −42.6 dB at 12.1 GHz. The enhanced EM-wave absorption performance was mainly ascribed to the increased interfacial polarization and dielectric loss that resulting from the introduction of MWCNTs. The result illustrated that the introduction of MWCNTs into magnetic materials can enable the efficient design of excellent EM-wave absorbers with low addition amount and coating thickness.