Electromagnetic wave absorption on resin composite including ferrite particles with concentration gradient

Abstract

The Fe₃O₄ particles were prepared from iron chloride by the hydrothermal reaction. The resultant Fe₃O₄ particles possessed good crystalinity when using the NH₄OH precipitant and showed the high saturated magnetization value of ca. 90 emu/g. Resin compacts including above ferrite powders were prepared using a centrifugal molding technique. The resultant concentration-gradient resin composites exhibited better broadband electromagnetic wave absorption than the homogeneous resin compacts (no gradation). Such absorption ability is responsible for the suppression of undesirable reflection on the incidence plane and effective thermal loss transducing of electromagnetic wave near the reflector where the magnetic powders are condensed.