Magnetic and thermal stabilities of FeSiB eutectic amorphous alloys: Compositional effects

Abstract

Magnetic and thermal stabilities of Fe-based amorphous alloys with high saturation flux density (Bs) are important for the application and understanding of the atomic interaction. Fex(Si3B13)(100-x)/16 (x = 86-71) eutectic amorphous alloys with superior manufacturability and Fe content limit were developed and the compositional effects were investigated. The alloys exhibit high Bs of 1.53–1.68 T, low coercivity of 2.2–4.3 A/m, and high permeability of 8.8–12.8 × 103. With the increase of Fe content, it is found that the Bs have an inflection point, the crystallization and Curie temperatures decrease drastically. The high Fe content alloys exhibit reduced thermal stabilities of magnetic properties, because the enhanced magnetic intercoupling effect is much lower than the weakened atomic bonding. For the alloys with x = 71–74, the decline rate of Bs is still lower than 10% at the extreme condition of 200 °C, while Bs of the alloy with x = 84 decreases more than 10% at 120 °C. The thermal stability of magnetic properties should be taken into consideration for the devices used in unique condition, especially for the high Bs amorphous alloys.