Electromagnetic wave absorption properties of composites with micro-sized magnetic particles dispersed in amorphous carbon

Composites with micro-sized magnetic particles dispersed in amorphous carbon were fabricated conveniently and economically by carbonizing polyacrylonitrile (PAN) fibers mixed with micro-sized iron particles under different temperatures. The composites were characterized by X-ray diffraction (XRD) and scanning electric microscope (SEM). The electromagnetic (EM) properties were measured by a vector network analyzer in the frequency range of 2-18 GHz based on which analog computations of EM wave absorption properties were carried out. The influences of temperature on phase composition and EM wave absorption properties were also investigated, indicating that the composites had good electromagnetic absorption properties with both electrical loss and magnetic loss. Effective reflection loss (RL < -10 dB) was observed in a large frequency range of 7.5-18 GHz with the absorber thickness of 2.0-3.0 mm for the paraffin samples with composite powders heated up to 750 degrees C and the minimum absorption peak around -40 dB appeared at approximately 10 GHz with matching thickness of 2.0 mm for the paraffin sample with composite powders heated up to 800 degrees C. (C) 2014 Published by Elsevier B.V.