Microstructure to magnetic behaviour relationship of annealed Fe–TM–B–Cu alloys

The evolution of magnetic microstructure for Fe80Zr4Mn3B12Cu1 and Fe82Zr4Nb3B10Cu1 alloys is investigated as a function of different amount of the crystalline phase. With progressing crystallisation the intergranual phase is depleted in iron, and structurally as well as magnetically distinct regions occur. Together with ferromagnetic bcc-Fe nanograins they affect the resulting macroscopic magnetic properties. Good soft magnetic properties as well as low core losses and high-quality frequency characteristics are found after 0.5 h annealing at 773 K for Fe80Zr4Mn3B12Cu1 and after 1 h annealing at 823 K for Fe82Zr4Nb3B10Cu1 alloys.