GRANULAR MAGNETIC COMPOSITES EMPLOYING COBALT-BASED AMORPHOUS-ALLOYS IN A POLYMERIC HOST

Cobalt based soft ferromagnetic amorphous alloys have unique propertie s which make these materials good candidates to be employed in magneti c composites prepared by dispersing granules of the alloy in a polymer ic host. These alloys have excellent soft magnetic properties which ar e minimally affected by external stresses induced during the processin g operations involved in the preparation of such a composite. Continuo us ribbons of a cobalt based amorphous alloy, Metglas 2705M, were cut into large aspect ratio flakes and blended into a polyethylene host in volume fractions ranging from 0.001 to 0.15. The relative magnetic pe rmeability values of the composites increased with increasing volume f raction of the amorphous alloy, reaching a value of 26 at the volume f raction 0.15. The magnetic properties of the composites exhibited two distinguishing features: The permeability values of these composite sa mples were found to vary only slightly, about 10%, as a function of fr equency in the range 10 Hz-100 kHz; the samples remained unsaturated u p to magnetic fields of 5800 A/m. These features are believed to be a result of the magnetic properties of the composite being heavily influ enced by the polymeric gaps between the magnetic filler particles.