Journal of magnetism and magnetic materials vol:203 pages:199-201
The influence of the annealing conditions in the microstructure and magnetic hysteresis loop of a Fe76Si10.5B9.5Cu1Nb3 alloy has been studied. For Joule-heated samples a magnetic softening is found earlier to the formation of BCC-Fe,Si nanocrystals and is related to structural relaxation phenomena. Magnetic hardening at the beginning of the nanocrystallization is not observed and coercivity remains unchanged with increasing the crystallized volume fraction. TEM observations show that the mean grain size is slightly smaller for Joule-heated samples (similar to 8 nm) than for those conventionally annealed (similar to 10 nm) for similar crystallized volume fraction. The onset of the second crystallization stage is characterized by a considerable magnetic hardening, less abrupt for Joule-heated samples than for furnace annealed ones, corresponding to the appearance of boride-type phases. (C) 1999 Elsevier Science B.V. All rights reserved.