The crystallization,microstructure,and soft magnetic properties of Fe52Co34Hf7B6Cu1 alloy are studied.Amorphous Fe52Co34Hf7B6Cu1 alloys are first treated by a pulsed magnetic field with a medium frequency,and then annealed at 100℃-400℃for 30 min in a vacuum.The rise in temperature during the treatment by a pulsed magnetic field is measured by a non-contact infrared thermometer.The soft magnetic properties of specimens are measured by a vibrating sample magnetometer（VSM）.The microstructure changes of specimens are observed by a Mossbauer spectroscopy and transmission electron microscope（TEM）.The results show the medium-frequency pulsating magnetic field will promote nanocrystallization of the amorphous alloy with a lower temperature rise.The nanocrystalline phase isα-Fe（Co） with bcc crystal structure,and the grain size is about 10 nm.After vacuum annealing at 100℃for 30 min,scattering nanocrystalline phases become more uniform,the coercive force and the saturation magnetization of the specimens are 41.98 A/m and 185.15 emu/g.
