Bulk metglas, finemet and nanoperm soft magnetic alloys prepared by ultra-high-pressure consolidation

Microstructure and soft magnetic properties of three bulk amorphous and nanocrystalline Fe78Si9B13, Fe73.5Cu1Nb3Si13.5B9 and Fe84Nb7B9 alloys prepared by consolidation at a ultra-high pressure (5.5 GPa) were investigated. The bulk alloys consisting of not only amorphous phase but also nanocrystalline α-Fe phase had high relative density (97.8–99.3%) and the sizes of nanocrystalline α-Fe phase were in the range of 10–20 nm. The spontaneous magnetization of bulk Fe78Si9B13, Fe73.5Cu1Nb3Si13.5B9 and Fe84Nb7B9 alloys are 1.08, 1.29 and 1.67 T, respectively while the coercivity are 285, 68 and 120 A/m, respectively. The high coercivity may be mainly due to the anti-size defects and internal stresses created by milling and consolidation and it could be decreased greatly after annealing.