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

Abstract

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 9.75wt% Fe, 7.98wt% Co, 4.13wt% P and 78.14wt% Ni. The Ni–Co–Fe–P alloy plating was stable in the air and the plated flake graphite was magnetic. The complex relative permittivity (ɛ=ɛ′−jɛ″) and permeability (μ=μ′−jμ″) of the samples were measured in the range of 0.1–10GHz. 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 3mm was −12.8dB at 4.6GHz. The plated flake graphite is a kind of ideal microwave absorbing material.