Relationship between microstructures and soft magnetic properties of simultaneously P and Cu-added Fe-Nb-B ribbon alloys

Abstract

The additional effect of P and Cu on the magnetic properties of Fe-Nb-B nanocrystalline soft magnetic alloys was investigated from the viewpoint of microstructures. Mean size of α-Fe grain for both Fe83.8Nb 6.6B9.6, and Fe83.7Nb6.6B 8.6P1Cu0.1 ribbon alloys are measured to be about 8.5 nm, and size distribution of those are measured to be 0.391 and 0.236. respectively, using an oval approximation for shape of α-Fe grains. Values of coercivity for Fe83.8Nb6.6B9.6 and Fe83.7Nb6.6B8.6P1Cu0.1 alloys calculated using a two-phase random anisotropy model are 6.73 and 4.93 A·m-1. and measured ones are 8.64 and 3.74 A·m -1. respectively. The improvement probably originates from the decrease in the distribution of the α-Fe grain size in the crystallized structure by the simultaneous addition. © 2008 The Japan Institute of Metals.