Study of order-disorder effect on magnetic properties of rapidly quenched Fe-6.5 wt% Si alloys

Microcrystalline ribbons of Fe-6.5 wt% Si alloy prepared by planar flow on Cu-Be wheel are used. Grain growth during isochronal annealing is measured. We confirmed by X-ray diffraction, transmission electron microscopy and Vicker's microhardness the different phase domains of A 2 . B 2 and DO 3 . Ordering kinetics are studied by Vicker's microhardness. DO 3 phase hardens the material whereas B 2 softens it. The effect of ordering on the magnetic properties as induction, coercive force, permeability and losses, is studied. H c and P 1 decrease respectively from 112 to 20 A/m, and 4 to 0.7 mw/cm 3 as grain diameter increases from 10 to 150 μm. μ max increases from 3100 to 22000 for the same increasing of grain diameter. The ordering effect is smaller than the grain size one, so it does not show for 300 μm grain diameter samples. The order-disorder effect on magnetic properties is insignificant with regard to the grain size one.