Effect of copper addition on crystallization and properties of hafnium containing HITPERM alloys (invited)

This paper presents properties and nanocrystallization characteristics of HITPERM based Fe68.8Co17.2Hf7Cu1B6 and Fe69.6Co17.4Hf7B6 alloys. Both alloys differing only in copper content were subjected to series of characterizations in order to study the effect of copper. Evolution of magnetic properties as a function time has been investigated by isothermal annealing experiments and optimum annealing conditions of amorphous precursors have been reported. Resulting magnetic properties (ac and dc) measured at room temperature are presented. Nanocrystallization kinetics studied by using time dependant magnetization measurements was discussed in the framework of Johnson–Mehl–Avrami model. Results of thermal stability measurements conducted in air at 500 K for up to 1000 h are reported.