Enhanced microwave absorption in nickel/hexagonal-ferrite/polymer composites

Abstract

Ni/hexagonal-ferrite (Co2Z or Zn2Y barium ferrites)/polymer composites were prepared for electromagnetic interference (EMI) shielding materials. In comparison with the hexagonal-ferrite/polymer or Ni/polymer composites, such three-phase composites exhibit excellent microwave absorption properties in the X-band frequency range, strongly depending on the combination of these three phases. For the Ni∕Co2Z/polymer composites with volume fraction ratio of Ni/ferrite equal to 0.70∕0.30, the EMI shielding effectiveness (SE) of the composites with a thickness of 2mm can be as high as ∼67dB. The high EMI SE of the composites and much larger contribution to total EMI SE from absorption than from reflection suggest that these composites would be very promising for applications as thinner and lighter EMI absorption materials.