Effect of Crystallization Condition on the Microwave Properties of Fe-based Amorphous Alloy Flakes and Polymer Composites

The electromagnetic (EM) wave absorption properties with a variation of crystallization temperature have been investigated in a sheet-type absorber made of the amorphous Fe73Si16B7Nb3Cu1 Finemet powder. With the variation of the annealing temperature, the magnetic and dielectric properties of the crystallized Fe-based absorber with a nano-structure were changed. The complex permittivity increased with increasing the annealing temperature, whereas the complex permeability was maximized after annealing at 530 degrees C for 1 hour. The absolute value of the reflection parameter, vertical bar S-11 vertical bar, increased with increasing annealing temperature of the nanocrystalline alloy powder. On the contrary, the transmission one, vertical bar S-21 vertical bar, showed the highest value after annealing at 530 degrees C for 1 hour, which is regarded as the optimum temperature for the improvement of EM wave absorption properties.