E. Ferrara et al., ROLE OF MATERIAL PURITY ON THE STRUCTURAL AND MAGNETIC-PROPERTIES OF RAPIDLY SOLIDIFIED FESI 6.5 WT-PERCENT ALLOYS, Journal of magnetism and magnetic materials, 133(1-3), 1994, pp. 366-370
A study has been made on the structural and magnetic properties of rap
idly quenched FeSi 6.5 wt% alloys, obtained from high purity (HP) and
commercial purity (CP) master alloys and characterised upon a range of
annealing treatments. Superior magnetic behavior is exhibited by the
HP alloys after annealing, which correlates with enhanced growth of a
favourable cube-on-face crystallographic texture. As suggested by meta
llographic analysis, a surface energy mechanism appears to control the
evolution of such texture, with a critical role being played by solut
e oxygen. Mechanical strength and ductility also appear improved in th
e HP samples. Substantial loss of Si and weakening of the texture are
however observed after high temperature annealing (T > 1200-degrees-C)
, with ensuing deterioration of the material soft magnetic properties.
It is concluded that optimum dc and high frequency magnetic behavior
of HP and CP alloy ribbons requires annealing treatments at temperatur
es around 1100-1150-degrees-C, where the achieved material structure p
rovides minimum losses and maximum permeability and the high Si concen
tration of the as-quenched material is retained.