INFLUENCE OF THE ELEMENTS SI B ON THE STRUCTURE AND MAGNETIC-PROPERTIES OF NANOCRYSTALLINE (FE,CU,NB)(77.5)SIXB22.5-X ALLOYS/

The influence of the silicon and boron contents on the structure and m agnetic properties of Fe74.5Cu1Nb2SixB22.5-x (at%) nanocrystalline all oys, with x = 9.5-17.5, has been investigated. The results show that t he lattice constants and Curie temperatures of the nanocrystalline all oys decrease linearly with increasing x. We deduce that the silicon co ntent x(alpha) in the grains increases linearly with increasing x, and obtain the relation x(alpha) = 0.626x + 10.5. The lambda(s) values of the alloys decrease with increasing Si content for the nanocrystallin e state, but increase for the as-quenched state. For the alloys anneal ed at a certain temperature, the volume fraction V-x of nanoscale grai ns is related to the Si and B contents of the alloys. V-x increases wi th increasing x (decreasing B content). Within the range of compositio ns studied, the nanocrystalline alloy has the optimum soft magnetic pr operties when x = 14.