Patent ID: 7905966

Claim:
A process for the manufacture of a strip made of nanocrystalline material which is obtained from a ribbon cast in an amorphous state, said strip having the atomic composition: [Fe 1−a−b Co a Ni b ] 100−x−y−z−α−β−γ Cu x Si y B z Nb α M′ β M″ γ wherein M′ is at least one of the elements V, Cr, Al and Zn, and M″ is at least one of the elements C, Ge, P, Ga, Sb, In and Be, with: a≦0.07 and b≦0.1 0.5≦x≦1.5 and 2≦α≦5 10≦y≦16.9 and 5≦z≦8 β≦2 and γ≦2 by subjecting the amorphous ribbon to a crystallization annealing in which the ribbon is subjected to the annealing in the unwound state, in forward progression through at least two S-type units and under tension in a substantially longitudinal axial direction of the ribbon, so that the ribbon is maintained at an annealing temperature of between 530° C. and 700° C., for a period of time of between 5 and 120 seconds, under an axial tensile stress of between 2 and 1000 MPa, the tensile stress to which said amorphous ribbon is subjected, its rate of forward progression during said annealing, the annealing time and the annealing temperature being chosen so that the cross section profile of the strip is not Ω-shaped and exhibits a maximum deflection of the transverse cross section of the strip of less than 3% of the width of the strip.