PRODUCTION OF FLAKY FE-BASED AMORPHOUS POWDERS BY A 2-STAGE QUENCHINGTECHNIQUE AND THEIR MAGNETIC-PROPERTIES

Amorphous Fe78Si9B13 and (Fe0.78Si0.09B0.13)97Cr3 powders were produce d by the two-stage quenching technique. These amorphous powders have a flaky morphology, with a disk or an ellipsoidal shape. The thickness is as small as 1-3 mum and the aspect ratio is as large as 20-300. The composite consisting of the flaky amorphous powders embedded in pheno l resin exhibits soft magnetic properties of a magnetic induction of B 8k = 0.54 T, maximum permeability mu(max) = 220 and coercive force H(c ) = 264 A m-1 for an Fe78Si9B13 composite core. It should be noted tha t the B8k Value is 2.1 times as high as that for the composite of amor phous Co-Fe-Si-B flaky powders and resin. The mu' value of the composi te core made from insulated flaky powder and phenol resin remains almo st unchanged in the high frequency range up to 1 0 000 kHz. Judging fr om the combined characteristics of the unique powder morphology and th e magnetic properties inherent to the Fe-based amorphous phase, the fl aky amorphous powders are concluded to have an enhanced engineering po tential.