By rapid quenching methods, ribbon‐form Sendust alloys, silicon‐iron ribbons Fe100−xSix(4 wt&percent;<x<10 wt&percent;) in the crystalline state as well as iron‐boron and iron‐cobalt‐silicon‐boron ribbons in the amorphous state were prepared. All of the ribbons obtained were remarkably flexible. The magnetostriction constant became zero at about the composition Fe92.5Si7.5and Fe84.74Si9.71Al5.55. The coercive force Hcand the initial permeability &mgr;iin a Sendust straight ribbon with Fe84.9Si9.62Al5.48were 24 mOe and 30000 respectively after annealing. The magnetostriction constants in Fe100−xBxamorphous ribbons became larger by annealing at 300°C for 3 hours in Ar atmosphere and reached 49×10−6at x=12.