Piezomagnetic properties and shielding properties of amorphous and nanocrystalline powders / butyl rubber composite films

The composite films of amorphous and nanocrystalline Fe_73.5Cu₁Nb₃Si_13.5B₉ powders/butyl rubber were prepared by pressing in the mold to shape. The piezomagnetic properties of composite films were studied in the temperature range of 20-50 Celsius degree with theshielding properties in the frequency band (30kHz-6000MHz) of electromagnetic wave. The results show that when the microstress below 0.09MPa and testing frequency below 200kHz, the piezomagnetic properties are the best and theirs piezomagnetic properties increase as temperatures increase, the piezomagnetic properties of amorphous composite films are the best at 40 Celsius degree. Within frequency band (30kHz-6000MHz) of electromagnetic wave, the films have good characteristics of shielding high-frequency and broad-frequency electromagnetic waves. The shielding properties are improved significantly as the content of powder or the thickness of materials increases. Shielding effectiveness above 15dB is obtained at certain experimental parameters.