Magnetic Properties of Fe_(73.5)Si_(13.5)B_9Cu_1Nb_3 Soft Magnetic Alloy crystallized in Nitriding-Atmosphere

摘要

Amorphous Fe_(73.5)Si_(13.5)B_9Cu_1Nb_3 alloy was crystallized in nitriding atmosphere of mixture gas of NH_3 and hydrogen. The crystallization at 823K showed the high electrical resistivity ranging from 494 to 538 mu OMEGA-cm, which was higher level compared with nano-crystalline Fe_(73.5)Si_(13.5)B_9Cu_1Nb_3 alloy with a resistivity of about 110 mu OMEGA-cm. Through the nitridation treatments, the amorphous alloy was transformed into nano-sized crystalline Fe_3Si including iron nitrides such as gamma' -Fe_4N phases. EPMA-concentration depth profiles confirmed an existence of nitrogen-rich region on the surface of the alloy ribbon, leading to the preferential formation of gamma' -Fe_4N phase. The formation of gamma' -Fe_4N phase leaded to an increase of the resistivity and provided stable permeability and a low core loss at high frequency.