Evaluation of Composites Containing Hollow Ni/Fe-Co Fibers on Near-Field Electromagnetic Wave Absorbing Properties
In order to develop an effective near-field electromagnetic (EM) wave absorber, we have fabricated polymeric thin films including hollow metallic microfibers. Hydrolyzed polymer micro fibers (~2.5 ㎛) were used as a substrate material for the electroless metal plating. Nickel and subsequent Fe-Co metal layers were coated on the surface of activated polymer fibers and then heat treatment for the hollow structure as well as the densification of metallic layers was performed under the Argon atmosphere. Unlike conventional particulate or flaky metal powders, these fibers can play a significant role in elevating the magnetic property of polymer films, resulting in the increased efficiency of EM absorbing properties. In addition, their hollow structure can also lower their apparent density. SEM and EDS analysis were carried out to verify the morphology and metal compositions. Polymeric thin films containing hollow Ni/Fe-Co micro fibers were prepared to investigate the effect of metal compositions, filler distribution and heat treatment conditions on not only the near-field absorbing performance, but also magnetic properties such as permeability and magnetization. For the measurement of near-field EM absorbance in the frequency range of ~6GHz, micro strip line and network analyzer were used.
Joong Hee Lee
J. W. Yi et al., "Evaluation of Composites Containing Hollow Ni/Fe-Co Fibers on Near-Field Electromagnetic Wave Absorbing Properties", Advanced Materials Research, Vols. 123-125, pp. 1223-1226, 2010