Optimizing the magnetic properties of Fe-based amorphous powder by adjusting atomic structures from vitrification at different temperatures

Abstract

We present variation of the magnetic properties of Fe77.8Nb0.2B14P6C2 amorphous alloys vitrified at different temperatures by changing the atomic structures dependent on the critical cooling rate. The thermophysical properties of the amorphous state achieved after quenching the melt with cold nitrogen atomization gas are compared with those obtained using hot nitrogen gas with a temperature corresponding to the supercooled liquid of the alloy above the glass transition (T-g) but below crystallization temperature (T-x). The differently vitrified Fe77.8Nb0.2B14P6C2 glasses represent different states of high pressure gas atomized amorphous powder at different temperatures obtained by adjusting the gas temperature during the atomization process. The magnetic properties of these different amorphous powders are also investigated. The saturation magnetic flux density of slowly cooled Glass2 is 1.38 T with 450 A/m coercivity corresponding to "semi-soft" magnetic materials. The fast cooled Glass1 powder shows typical soft magnetic properties with lower coercivity (174 A/m), even though the saturation magnetization flux densities are similar in both identical compositions of amorphous powder due to its entropy difference related to the formation of clusters. We can control the magnetic property of amorphous materials from soft to half-soft by adjusting freezing temperature and ordering of atoms. Published under license by AIP Publishing.