Development of Novel Fe Based Nanocrystalline FeBNbPSi Alloy Powder with High Bs of 1.41T

Abstract

The possibility of the powderization of the precursor with a single amorphous phase was investigated in the FeBNbP and the FeBNbPSi nanocrystalline alloy powders. The Fe90-XBxNb7P3 (x=9, 10), the Fe79.5B9.5Nb7P3Si1 and the Fe82-xB9Nb6P3Six (x=2, 3) powders were prepared by the gas atomization method using high pressure water for rapid quenching. The crystallization by abnormal grain growth was shown by cross sectional images and SAED pattern in the as-atomized Fe81B9Nb7P3 particle. On the other hand, the as-atomized particle as a precursor exhibiting low Hc of 141 A/m with single amorphous phase was observed from a cross sectional image and SAED pattern in the Fe80B10Nb7P3 nanocrystalline alloy powder. In addition, the stability of amorphous phase in the FeBNbP nanocrystalline alloy powder was also significantly improved by the addition of Si. The as-atomized Fe79.5B9.5Nb7P3Si1 nanocrystalline alloy powder with Si of 1 at% was decreased the crystallization peak compared with the Fe80B10Nb7P3 nanocrystalline alloy powder without Si. In particular, the as-atomized Fe79B9Nb6P3Si3 alloy powder with Si of 3% as a precursor powder of nanocrystalline alloy exhibited the excellent magnetic softness of low Hc of 53 A/m compared to ordinary Fe73Si11B11Cr3C2 amorphous and Fe73.5Si13.5B9Nb3Cu1 nanocrystalline alloy powders. Furthermore, the nanocrystallized Fe79B9Nb6P3Si3 powder at 873K achieved both high Bs of 1.41T and low Hc of 37A/m compared to ordinary amorphous, and nanocrystalline alloys. Therefore, we concluded that the novel FeBNbPSi nanocrystalline alloy powder with both high Bs and low Hc was developed for magnetic core of inductor products.  Fig.1 (a) SEM image of the particle cross section with the Fe81Nb7B9P3, (b) TEM bright field image of amorphous and crystallization region with the Fe81B9Nb7P3, (c), (d), (e) SAED pattern of a region with A, B and C, (f) SEM image of the particle cross section with the Fe80B10Nb7P3, (g) TEM bright field image of amorphous region with the Fe80B10Nb7P3, (h) SAED pattern of D region.  Table. 1 Average particle size and magnetic characteristics of Fe90-XBxNb7P3 (x=9, 10), Fe79.5 B9.5Nb7P3Si1 and Fe82-xB9Nb6P3Six (x=2, 3) powders with ordinary FeSiBCCr and FeSiBNbCu powders.