Electromagnetic and oxidation resistance properties of core‐shell structure flaked carbonyl iron powder@SiO2 nanocomposite. Issue 6 (6th March 2017) - Li, Wangchang
Abstract : The SiO2 coated sphere and flaky carbonyl iron powders (CIPs) heterogeneous nanocomposites have been prepared through the Stöber method and subsequently, through an annealing process for eliminating the crystal defect and enhancing the insulation and oxidation resistance of SiO2 shell. The CIP@SiO2 heterogeneous nanocomposites were characterized by X‐ray diffraction (XRD), Fourier Transform infrared (FTIR) spectroscopy, Scanning Electron Microscopy (SEM), Thermogravimetric (TG) analysis and Vector Network Analyzer (VNA). The CIP surface had been successfully assembly‐coated with nano SiO2 layer, obtained by the SEM, XRD, and FTIR. Both the annealing treatment and the SiO2 shell can synergetically improve the oxidation resistance property due to the reduction of defects and residual stress, and isolation of oxygen, respectively. Changed everywhere permittivity (magnetic permeability) by effective permittivity (magnetic permeability). The real part of the permittivity of the nanocomposite decreased significantly, while the imaginary part of permittivity remained the same indicating the increase of dielectric loss. The permeability decreased slightly for the SiO2 insulated shell blocking the magnetic path. Hence, the electromagnetic match property was greatly improved by coating SiO2 insulated shell, and this composite showed a broad absorption band.