Influence of Si addition on thermal stability and soft magnetic properties for Fe–Al–Ga–P–C–B glassy alloys

The thermal stability of the supercooled liquid region (ΔTx), defined by the difference between crystallization temperature (Tx) and glass transition temperature (Tg), and soft magnetic properties were investigated for Fe70Al5Ga2P12.65-xC5.75B4.6Six(x=0–4) and Fe77Al2.14Ga0.86P11-xC5B4Six(x=0–3) glassy alloys. The thermal stability, glass forming ability and effective permeability (μe) at 1 kHz are improved with the replacement of P by 1–3 at. % Si for Fe70Al5Ga2P12.65-xC5.75B4.6Six and by 1–2.6 at. % Si for Fe77Al2.14Ga0.86P11-xC5B4Six. The ΔTx and the maximum thickness for glass formation (tmax) reach ma- ximum values of 60 K and 280 μm, respectively, for Fe70Al5Ga2P12.65-xC5.75B4.6Six and 34 K and 220 μm, respectively, for Fe77Al2.14Ga0.86P11-xC5B4Six at Si(at. %)/(Si(at. %)+P(at. %))=0.24. Core losses for Fe77Al2.14Ga0.86P8.4C5B4Si2.6 glassy alloy is much lower than that for amorphous Fe–Si–B alloy at the sheet thickness more than 70 μm. Therefore, it can be said that the Fe–Al–Ga–P–C–B–Si glassy alloys are useful for inductive applications because of their bulky shape and good soft magnetic properties. © 1998 American Institute of Physics.