Effect of Ge on soft magnetic properties at elevated temperature for Si-rich Finemet-type alloy

The results obtained by partially substituting Ge for Fe in the Fe-based nanocrystalline alloy for improving the magnetic properties at high temperatures are presented in this work. These studies were performed on the Fe74.5-xGexCu1Nb2Si17.5B5(x = 2.5, 5, 7.5) alloys. The nanocrystallization and the Curie temperature are dependent on the Ge concentration. The onset temperature of primary crystallization decreases with the increase of Ge, indicating that the dual-phase nanocrystalline structure could be formed at a relatively lower temperature compared with the Ge-free alloy. For the alloy with x = 2.5at%, the Curie temperature of the amorphous alloy is enhanced to 405 degrees C. The initial permeability mu(i) of 540 degrees C-annealed alloy possesses a relatively large value of 5000 until 600 degrees C. Such a magnetic softness at elevated temperature is superior to that of Finemet-type Fe-based nanocrystalline alloys ever reported.

Automated summary

This study investigates the effects of partially substituting Ge for Fe in Fe-based nanocrystalline alloys for improving magnetic properties at high temperatures. The results show that Ge concentration plays a key role in nanocrystallization and Curie temperature.