Abstract
Nanocrystalline Fe74·29–xCuxNb2·9Si13·56B9·25 (x = 0·8–1·1) alloy ribbon cores were prepared by the single roller melt spinning technology and the subsequent annealing treatment. The Cu content dependences of the thermal stability, crystallisation behaviour, and soft magnetic properties of Fe74·29–xCuxNb2·9Si13·56B9·25 alloys were investigated. The alloy’s coercivity Hc firstly increased and then decreased with increasing Cu content from 0·8 to 1·1, while the saturation induction Bs and the effective permeability μe showed the opposite variation tendencies. The alloy with the Cu content of 0·9, which had the minimum Hc of 0·59 A m−1, the maximum Bs of 1·26T and the maximum μe of 120800, was found to exhibit the relatively best soft magnetic properties. When the Cu content was more than 0·9, the soft magnetic properties deteriorated obviously. This is due to the growth of the alloy’s nanograins caused by the increase in the Cu content and suggests that the proper Cu content is effective to improve the soft magnetic properties.
This work was supported by the Natural Science Foundation of Education Department of Anhui Province (KJ2012A227). The authors are grateful to Mr J. C. Zhang in the Instrumental Analysis Center of Hefei University of Technology, for performing helpful XRD measurement. We also thank Dr. L.F. Wang of Hefei University of Technology for fruitful discussions.