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)–5 amorphous alloys with x = 0–5 and y = 0–5 were examined. Primary crystallization temperature of Fe62Co10Si15–xB13Nbx and Fe62Co10Si10B18–yNby alloys 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.