New Fe-metalloids based nanocrystalline alloys with high Bs of 1.9T and excellent magnetic softness

Abstract

The melt-spun Fe83.3–84.3Si4B8P3–4Cu0.7 alloys have a heterogeneous amorphous structure including a large amount of α-Fe-like clusters. Compared with the FeSiB alloys, the particle size rapidly decreases from several hundred nanometers to 2–3nm due to the proper amounts of simultaneous P and Cu additions. By controlling the crystallization process, a homogeneous nanocrystalline structure composed by small α-Fe grains with size of 10–17nm in diameter can be realized from the heterogeneous amorphous alloys. The nanocrystallized Fe83.3–84.3Si4B8P3–4Cu0.7 alloys show the extremely high saturation magnetic flux density of 1.88–1.94T sufficiently near to 1.97T of Fe-3.5mass%Si crystalline soft magnetic alloys, and exhibit low coercivity of less than 10A∕m and higher effective permeability of 16 000–25 000 at 1kHz due to the simultaneous realization of the homogeneous nanocrystalline structure and the small magnetostriction of (2–3)×10−6. In addition, the nanocrystalline alloys exhibit the superior core loss to the representative Fe78Si9B13 amorphous alloy at 50Hz.