A Polypyrrole/CoFe₂O₄/Hollow Glass Microspheres three-layer sandwich structure microwave absorbing material with wide absorbing bandwidth and strong absorbing capacity

A new PPy/CoFe₂O₄/HGMs microwave absorbing composite particle with three-layer sandwich structure, comprising cobalt ferrite (CoFe₂O₄) and polypyrrole (PPy) coating on the surface of hollow glass microspheres (HGMs), was synthesized by the method of co-precipitation and in situ polymerization. The surface morphology, phase structure and chemical component of the composite had been characterized by scanning electron microscope and X-ray diffractometer. The results indicated HGMs were coated by CoFe₂O₄ completely and the obtained CoFe₂O₄/HGMs composites were warped by PPy. The conductivity and the saturation magnetization Ms of the resulting PPy/CoFe₂O₄/HGMs composites are 0.09 S/cm and 46 emu/g, respectively. The vector network analyzer showed the composite performed better microwave absorption ability than that of PPy and PPy/HGMs. The reflection loss of the composite with 2.58 mm thickness is more than−10 dB which means over 90 % microwave is absorbed in X-band (8.38–12.4 GHz). The ternary composite that has light weight, wide absorbing bandwidth, strong absorbing capacity and conductivity can be an attractive candidate in the field of microwave absorption.