Effect of Magnetic Pulsing and Low-Temperature Vacuum Annealing on the Soft Magnetic Properties of Hitperm Amorphous/Nanocrystalline Alloy

We studied soft magnetic properties of FeCoHfBCu amorphous/nanocrystalline alloy treated by medium-frequency magnetic pulsing (frequency 1500-2000Hz, field intensity 200-250Oe) and vacuum annealing at low temperature. The results of Mössbauer spectroscopy and transmission electron microscope show that the treating of magnetic pulsing with a medium frequency can introduce the nanocrystallization of amorphous FeCoHfBCu, precipitation of nm phase α-Fe(Co). And, with the increasing of pulsed frequency and field itensity, the crystalized volume friction increases from 24.71% to 35.2%. The low-temperature vacuum annealing for 100°C/30min of magnetic pulsed samples further improved the soft magnetic properties of nanocrystalline alloy. As compared with the amorphous state, the magnetic coerelvity decreaced from 103.4A/m to 34.0A/m, the saturated magnetization decreased from 160.47emu/g to 149.32emu/g. (paper)