Microstructures and soft magnetic properties of Fe73.5-xCu1Nb3Si13.5B9Yx (x = 0–1.5) alloys

Abstract

Adding Y to replace Fe in composition of Finemet alloy, and prepare alloy samples of Fe73.5-xCu1Nb3Si13.5B9Yx (x = 0, 0.5, 1.0, 1.5) to study the structures and soft magnetic properties. After vacuum melting and rapid cooling, the rapidly solidified as-cast alloy ribbons were prepared, and Fe73.5-xCu1Nb3Si13.5B9Yx (x = 0, 0.5, 1.0) as-cast samples have single phase of amorphous structure. So the alloys are amorphous by rapid cooling within the addition of Y less than 1.0%. After annealing, nanocrystalline appeared in the matrix, the nanocrystals are randomly oriented and the grain size of Fe73Cu1Nb3Si13.5B9Y0.5 alloy is around 10 nm, the ordered crystal planes can be observed, it is consistent with α-Fe(Si). From the APT we can see the distribution of elements, Fe and Si are mostly in the grain, Nb and B are in the grain boundary and amorphous phase, and Cu is in clusters. The Fe73Cu1Nb3Si13.5B9Y0.5 alloy has the best soft magnetic properties, with the μi and μm values ​​are 149.93 k and 1213.00 k, respectively, which are 22.19% and 43.72% higher than Finemet. The Fe73Cu1Nb3Si13.5B9Y0.5 alloy also has excellent soft magnetic properties at high temperature, when the ambient temperature at 120 °C and 150 °C, the μe values increased by 42.21% and 40.95% than Finemet at 1 k Hz, respectively; and increased by 14.30% and 19.70% at 10 k Hz. In addition, the Fe72.5Cu1Nb3Si13.5B9Y1 alloy has the lowest coercivity value of 0.40 A/m.

Keywords

• Fe-based nanocrystalline alloy
• Soft magnetic properties
• Rare earth Y