Quenching-rate dependence of the magnetic and mechanical properties of nanocrystalline Fe73.5Cu1Nb3Si13.5B9 ribbons obtained by Joule heating

Four [Fe.sub.73.5][Nb.sub.3][Cu.sub.1][Si.sub.13.5][B.sub.9] ribbons obtained by melt spinning with different quenching rates were submitted to direct current (DC) Joule-heating treatment in vacuum. On-line measurements of the electrical resistance were performed in the course of Joule heating in order to study the development of the nanocrystalline phase. The results show that the nanocrystallization kinetics is strongly dependent on the initial degree of structural disorder. The increase in both initial magnetic permeability and brittleness upon nanocrystallization were observed to be affected by the initial topological disorder.