PING 2019 is organized with the support of funds for specific university research project SVK1-2019-002.In this work, the influence of heat treatment process on structure and magnetic
properties for rapidly quenched Fe72Ni8Nb4Si2B14 alloy are reported. Firstly, for
amorphous ribbons the onsets of crystallization process for bcc-Fe type phase (primary
crystallization) and bct-Fe3B type phase (secondary crystallization) are defined by
thermal analysis using heating rate of 10°C/min. Then basing on measured values the
classical heat treatment process (with heating rate 10°C/min) in vacuum for wound
toroidal cores is optimized to obtain best soft magnetic properties (B(H) dependencies
and magnetic core loss Ps) at frequency 50 Hz. For heat treated samples the X-ray
diffraction method is used to determine the unit cell parameters of bcc-Fe type
nanocrystallites as well as their average crystallite size. Therefore, for optimal heat
treated sample the complex magnetic permeability in the frequencies 106 -109 Hz for
temperature range from -50°C to 100°C is measured and in the frequencies 104 -108
Hz at room temperature
