日本金属学会誌

J. Japan Inst. Metals, Vol. 51, No. 4 (1987),
pp. 263-270

Crystallization Process and Magnetic Properties of Fe100-XBX(10≤ X ≤ 35) Amorphous Alloys and Supersaturated Situation of Boron in α-Fe

Toshio Nakajima1, Eiji Kita2 and Hiromitsu Ino3

1R & D Laboratory, TOPY Industries Ltd., Toyohashi
2Institute of Applied Physics, University of Tsukuba, Sakura-mura, Ibaraki
3Institute of Industrial Science, University of Tokyo, Tokyo

Abstract:

Amorphous specimens were prepared in the range of 10 ≤ X ≤ 35 at%B by a single roller method. The crystallization process and the B concentration dependence of the Curie temperature were examined by differential scanning calorimetry, X-ray diffraction, Mössbauer spectroscopy and magnetic measurement.
Two step crystallization was observed in the specimens of X<17: Amor.→Amor.+B supersaturated bcc phase (α-Fe(B))→t-Fe3B+α-Fe. The single α-Fe(B) phase was not observed. The transition temperature from t-Fe3B to stable (α-Fe+t-Fe2B) sensitively depends on B content in the alloys. The crystallization temperature (TX) of the amorphous alloys was almost unchanged in 17≤ X ≤ 31, but increased remarkably in the high boron concentration of X ≥qq33, where the decomposition products consisted of t-Fe2B and o-FeB.
The Curie temperature (TC) of the amorphous phase is as low as 480 K at X=10, increased with increasing B content up to 820 K and then decreased in the high B concentration alloys of X>28.
The single α-Fe(B) phase was not detected in the as quenched specimens of X=8 and 10. The phase coexisted with the o-Fe3B and amorphous phases. The lattice parameter of the phase was 0.28610 nm which was smaller than that of pure iron by 2/1000, indicating the substitutional occupation of boron atoms in the bcc lattice.


(Received 1986/12/1)

Keywords:

iron-boron alloys, amorphous, single roller method, crystallization process, magnetic properties, Curie temperature, supersaturated solid solution


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