The effect of Nb addition on the thermal stability and magnetic properties of Fe-based amorphous alloys with a wide supercooled liquid region

Abstract

We have examined the effect of Nb addition on the thermal stability of the supercooled liquid before crystallization, the glass-forming ability and magnetic properties for the amorphous alloy series Fe73NbxAl5-xGe2P10C6B4 and Fe63Co7NbxZr10-xB20. The supercooled liquid regions (ΔTx = Tx - Tg) have maximum values of 66 and 79K, respectively, for Fe73Nb1Al4Ge2P10C6B4 and Fe63Co7Nb4Zr6B20 alloys. The saturation magnetization σs of the Fe73NbxAl5-xGe2P10C6B4 alloy system is much higher than that of the Fe63Co7NbxZr10-xB20 alloy system and is almost unchanged with an increasing Nb content from 0 to 3 at%. But the σs of the Fe63Co7NbxZr10-xB20 alloys decreases linearly with increasing Nb content. The coercive force Hc of the two alloy series can have a minimum value of 31A/m for Fe73Nb1Al4Ge2P10C6B4 and 37A/m for Fe63Co7Nb4Zr6B20. All these values are for the ribbons annealed at 773 and 873K for 15min in vacuum.