Microwave absorption property of Ni-Co-Fe-P-coated flake graphite prepared by electroless plating

Ni-Co-Fe-P alloy coating was covered on surface of flake graphite by electroless plating process. Morphology, composition, structure, magnetic property and microwave absorbing property of the Ni-Co-Fe-P alloy plating were characterized by scanning electron microscopy (SEM), energy diffraction spectrum (EDS), X-ray diffraction (XRD), Fourier transform infrared spectrometer (FTIR), vibrating sample magnetometer (VSM) and vector network analyzer, respectively. The results indicated that uniform Ni-Co-Fe-P alloy plating was deposited on surface of flake graphite by the electroless plating and the coating was composed of 9.75 wt% Fe, 7.98 wt% Co, 4.13 wt% P and 78.14 wt% Ni. The Ni-Co-Fe-P alloy plating was stable in the air and the plated flake graphite was magnetic. The complex relative permittivity (epsilon = epsilon' - j epsilon '') and permeability (mu = mu' - j mu '') of the samples were measured in the range of 0.1-10 GHz. The reflection loss (RL) was calculated using the theory of absorbing wall, and the results showed that the minimum RL of the plated flake graphite with a thickness of 3 mm was -12.8 dB at 4.6 GHz. The plated flake graphite is a kind of ideal microwave absorbing material. (C) 2011 Elsevier B. V. All rights reserved.