A GHz range electromagnetic wave absorber with wide bandwidth made of FeCO/Y2O3 nanocomposites

Nanocomposites consisting of fine particles of FeCo (similar to 30 nm) and Y2O3 (similar to 15 nm) have been prepared from an intermetallic compound Y-2(Fe0.5Co0.5)(17) by melt-spinning techniques and subsequent hydrogenation-disproportionation and oxidation treatments. The electromagnetic (EM) wave absorption properties were characterized in a frequency range of 0.05-20.05 GHz. The measured real part (epsilon(r)'') and imaginary part (epsilon(r)'') of the relative permittivity were small and approximately constant in the 1-10 GHz range. The imaginary part of relative permeability mu(r)'' exhibited two resonant peaks and a high value over the 1-10 GHz range. As a result, the resin composites with 80 wt% FeCo/Y2O3 powders exhibited excellent EM wave absorption properties (reflection loss RL < -20 dB) in a frequency range of 2.7-8.1 GHz, with thickness of 2.2-5.7mm, respectively. A minimum RL of -43dB was observed at 5.6GHz with an absorber thickness of 3 mm. (C) 2004 Elsevier B.V. All rights reserved.