Effect of composition on the crystallization and magnetic properties of Fe–Co–Si–B–Nb amorphous alloys

The crystallization behavior and magnetic properties of Fe62Co10Si15−xB18−yNb(x + y)−5amorphous alloys with x = 0–5 and y = 0–5 were examined. Primary crystallization temperature of Fe62Co10Si15−xB13Nbx and Fe62Co10Si10B18−yNbyalloys increased with the addition of Nb. The primary and secondary crystallization temperatures were well separated when the Nb content is above 4 at%. The alloys with 15–18 at% B showed a distinct supercooled region. The Nb addition decreased the Curie temperature as well as room temperature saturation magnetization. The glassy-type Fe62Co10Si10B18 alloy exhibited good soft magnetic properties as well as a supercooled liquid region of 39 K. The finding of the glassy-type Fe-based alloy without Nb element exhibiting high Bs above 1.4 T is promising for future use as a soft magnetic glass material.