Microstructure and electromagnetic characteristics of Ni nanoparticle film coated carbon microcoils

• Published in: Journal of alloys and compounds 2009-06, Vol.478 (1), p.796-800
• Main Authors: Bi, Hui, Kou, Kai-Chang, Ostrikov, Kostya (Ken), Yan, Lu-Ke, Wang, Zhi-Chao
• Format: Article
• Language: English
• Subjects: Carbon microcoils; Chemical vapor deposition; Condensed matter: electronic structure, electrical, magnetic, and optical properties; Dielectric loss and relaxation; Dielectric properties of solids and liquids; Dielectrics, piezoelectrics, and ferroelectrics and their properties; Exact sciences and technology; Magnetic properties; Microwave and radio-frequency interactions (excluding resonances); Nanocomposites; Optical properties and condensed-matter spectroscopy and other interactions of matter with particles and radiation; Other interactions of matter with particles and radiation; Physics; Scanning electron microscopy
• ISSN: 0925-8388; 1873-4669
• DOI: 10.1016/j.jallcom.2008.12.053

Carbon microcoils (CMCs) have been coated with a Ni nanoparticle film using an electroless plating process. The morphology, the elemental composition and the phases in the coating layer, complex permittivity and permeability of the CMCs and Ni-coated CMCs were, respectively, investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS) and microwave vector network analysis at room temperature. A homogeneous dispersion of Ni nanoparticles on the outer surface of the CMCs was obtained, with a mean particle size of ∼34.4 nm and the phosphorus content of about 8.5 wt%. When comparing the coated and uncoated CMC samples, the real ( ɛ′) and imaginary ( ɛ″) part of the complex permittivity as well as dielectric dissipation factor ( tgδ ɛ = ɛ″/ ɛ′) of the Ni-coated CMCs were much smaller, while the real ( μ′) and imaginary ( μ″) part of the complex permeability and the magnetic dissipation factor ( t g σ μ = μ ″ / μ ′ ) were larger. The enhanced microwave absorption of Ni-coated CMCs resulted from stronger dielectric and magnetic losses. In contrast, the microwave absorption of uncoated CMCs was mainly attributed to the dielectric rather than magnetic losses.