Rapid-annealed FeSiBPCu nanocrystalline alloy with high Bs approaching 1.9 T and good bendability
Qian Zhang, Yang Meng, Chengliang Zhao, Chuntao Chang, Shujie Pang, Shaoxiong Zhou
Abstract
To promote energy savings, high efficiency and miniaturization of power electronic devices, Fe–Si–B–P–Cu nanocrystalline soft magnetic materials with high saturation magnetization ( B s ) parallel to that of the 6.5 wt% Si steel and low coercivity ( H c ) are desired. In this work, 30 μm-thick Fe 84 Si 3 B 10 P 2 Cu 1 and Fe 84.5 Si 3 B 9.5 P 2 Cu 1 (at.%) amorphous/nanocrystalline precursor ribbons were melt-spun, which has high Fe contents comparable to that of the 6.5 wt% Si steel. These ribbons consist of an amorphous matrix and pre-existing α-Fe of approximately 28–30 nm in size possessed relatively low and similar-value activation energy of nucleation and growth in the range of 224–249 kJ/mol. Which could induce strong crystallization competition and effectively suppress coarsening of the pre-existing α-Fe. The Fe 84 Si 3 B 10 P 2 Cu 1 nanocrystalline alloy obtained by rapid-annealing (∼100 °C/s) the amorphous/nanocrystalline precursor at 480 °C for 30 s (Fe84-480) exhibited a fine and uniform nanostructure containing α-Fe with small average grain size of approximately 23.1 nm and high volume fraction. The Fe84-480 alloy possessed a high B s of approximately 1.88 T, a low H c of 8.6 A/m, and good bendability revealed by relatively large bending fracture strain of ∼1.65%, making it a promising soft magnetic material for power electronic devices.