Amorphous ultra-fine powders in (Fe, Co or Ni)-B, Fe-Co-B, Fe-Ni-B and Co-Ni-B systems were produced by reduction of metal ions in an aqueous solution by use of KBH4. The powders have a spherical shape with diameters ranging from 5 to 20 nm. The boron concentration is in the range of 28 to 37 at% and the composition of metal elements can be controlled by changing the concentration of metal ions. Crystallization temperatures (Tx) and heats of crystallization for the (Fe-Ni)72B28 powders agree with those obtained for the amorphous alloys of the same composition produced by melt spinning. Furthermore, the compositional dependences of Tx, coercivity and magnetization are very similar to those obtained in the chemically synthesized (Fe-Co)63B37, (Fe-Ni)72B28 and (Co-Ni)67B33 amorphous powders and melt-spun (Fe-Co)78Si8B14, (Fe-Ni)78Si8B14 and (Co-Ni)78Si8B14 amorphous ribbons. It is concluded that there is no significant difference in the amorphous structure obtained in the chemically synthesized powders and the melt-spun ribbons, in spite of an essential difference in the formation mechanism of these amorphous alloys.
|Number of pages||11|
|Journal||Science Reports of the Research Institutes, Tohoku University, Series A: Physics, Chemistry and Metallurgy|
|Publication status||Published - 1989 Mar 1|
ASJC Scopus subject areas
- Condensed Matter Physics
- Metals and Alloys