Formation and magnetic properties of Fe-B-Si amorphous alloys

The magnetic properties and crystallization temperatures of alloys in the ternary Fe-B-Si system are reported. The Curie temperature increases slightly on replacement of boron by silicon. This results in a sharp ridge of relatively constant room-temperature saturation magnetization extending from Fe
80
B
20
to Fe
82
B
12
Si
6
. The coercivity exhibits a broad minimum, both before and after stress relief annealing, in the region around Fe
81
B
15
Si
4
and extending at least to Fe
77
B
13
Si
10
. The crystallization temperature increases with increasing silicon and with decreasing iron and boron. The alloys with silicon are generally easier to prepare in the amorphous state than the binary Fe-B alloys. Thus for the highest saturation magnetization alloy combined with ease of preparation, stability, and lowest losses, the alloys between Fe
81
B
17
Si
2
and Fe
82
B
12
Si
6
are preferred.