A study in Scientific Reports investigated the synthesis and characterization of a nanocomposite composed of FeNi₃-NiFe₂O₄-SiO₂ nanoparticles combined with multi-wall carbon nanotubes (MWCNT). The research focused on evaluating the electromagnetic interference (EMI) shielding properties of the composite, aiming to develop a lightweight, high-performance material for microwave technology applications.
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Background
The increasing prevalence of EMI in electronic systems has created a need for materials that combine efficiency, low weight, and multifunctionality. While effective in some contexts, traditional shielding materials often fall short in flexibility and versatility. Recent developments in nanotechnology have enabled the combination of magnetic-ceramic materials, such as FeNi₃-NiFe₂O₄-SiO₂ with conductive carbon-based components like MWCNT.
FeNi₃-NiFe₂O₄-SiO₂ contributes strong electromagnetic wave absorption properties due to its magnetic characteristics, while MWCNT improves electrical conductivity and structural stability. This study aimed to optimize the combined properties of these materials to create a composite with enhanced EMI shielding performance.
Method
FeNi₃-NiFe₂O₄-SiO₂ nanoparticles were synthesized using a coprecipitation process. Nickel sulfate and iron sulfate were dissolved, mixed under magnetic stirring, and refluxed for uniformity. Sodium hydroxide was added to adjust the pH to 10, facilitating precipitation. Hydrazine hydrate served as a reducing agent, and tetraethyl orthosilicate (TEOS) was used to promote silica formation. The precipitate was washed and dried at 50 °C.
The synthesized nanoparticles were combined with MWCNT to form the nanocomposite. Structural and morphological properties were analyzed using X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), and transmission electron microscopy (TEM). Raman spectroscopy confirmed the presence of MWCNT. EMI shielding effectiveness was measured in the X and Ku frequency bands.
Results and Discussion
The FeNi₃-NiFe₂O₄-SiO₂ nanoparticles exhibited spherical morphologies with an average diameter of 10 nm. FESEM images showed that the nanoparticles adhered to the MWCNT sidewalls, forming clusters along the nanotube surface. Raman spectroscopy identified the characteristic D and G bands of MWCNT, which are indicative of its electrical properties.
The addition of MWCNT significantly increased the electrical conductivity of the composite. This enhancement improved AC conduction and dielectric tangent loss, key parameters for EMI shielding. The nanocomposite demonstrated a shielding effectiveness of 25.29 dB at a thickness of 3.5 mm, indicating effective attenuation of electromagnetic waves. The shielding mechanism involved both absorption and reflection, supported by the magnetic and conductive properties of the composite.
The ferromagnetic nature of FeNi₃-NiFe₂O₄-SiO₂ contributed to wave absorption, while the MWCNT improved surface and interfacial polarization. These combined effects enhanced the overall shielding performance, making the material suitable for use in environments requiring effective EMI mitigation, such as microwave technology.
Conclusion
This study successfully synthesized and characterized a FeNi₃-NiFe₂O₄-SiO₂ nanocomposite with an EMI shielding effectiveness of 25.29 dB. The material’s properties result from the synergistic interaction between the magnetic-ceramic nanoparticles and the conductive MWCNT. The composite is lightweight, functional, and effective at attenuating electromagnetic waves, making it suitable for technological applications in electronics and telecommunications. Future work could explore optimizing synthesis processes and broadening the material’s applicability in advanced electronic systems.
Journal Reference
Dehghani-Dashtabi, M., Hekmatara, H. (2025). Structural, electrical and EMI shielding property of carbon nanotube decorated magnetic/ceramic nanoparticles. Scientific Reports. DOI: 10.1038/s41598-025-85378-4, https://www.nature.com/articles/s41598-025-85378-4
