T. Itoi et A. Inoue, Thermal stability and soft magnetic properties of Fe-Nb-B amorphous alloyswith high boron concentrations, MATER T JIM, 40(7), 1999, pp. 643-647
Ferromagnetic amorphous Fe-Nb-B alloys containing 30 at%B were found to exh
ibit a large supercooled liquid region with a temperature interval over 50
K before crystallization and the largest Delta T-x(=T-x-T-g) reaches 71 K f
or Fe62Nb8B30. The Delta T-x is strongly dependent on B content, while the
soft magnetic properties of saturated magnetization (I-s), permeability (mu
(e)) and saturated magnetostriction (lambda(s)) are dependent on Nb content
. The Fe62Nb8B30 amorphous alloy exhibits good soft magnetic properties of
0.68 T for I-s, 2.6 A/m for coercive force (H-c), 19300 for mu(e) at 1 kHz
and 7.7 x 10(-6) for lambda(s). The crystallization takes place through a s
ingle exothermic reaction, accompanying the simultaneous precipitation of t
he three crystalline phases of alpha-Fe, Fe2B and FeNb2B2. The crystallizat
ion mode which requires long-range atomic rearrangements plays a dominant r
ole in achieving the high stability of the supercooled liquid against cryst
allization.