Table of Contents
Journal of Metallurgy
Volume 2011, Article ID 910268, 5 pages
http://dx.doi.org/10.1155/2011/910268
Research Article

Amorphization, Crystallization, and Magnetic Properties of Melt-Spun Alloys

Liya Li1,2 and Wei Xie2

1State Key Laboratory for Powder Metallurgy, Central South University, Changsha 410083, China
2Faculty of Engineering and Industrial Sciences, Swinburne University of Technology, Melbourne, VIC 3122, Australia

Received 3 September 2010; Revised 30 November 2010; Accepted 5 January 2011

Academic Editor: Akihiro Makino

Copyright © 2011 Liya Li and Wei Xie. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Effects of Cr3C2 content and wheel surface speed on the amorphous formation ability and magnetic properties have been investigated for melt-spun ( ) alloys. Ribbon melt-spun at lower wheel speed (30 m/s) has composite structure composed of mostly SmCo7, a small amount of Sm2Co17, and residual amorphous phases. The grain size of SmCo7 phase decreases with the increase of Cr3C2 content . When melt spinning at 40 m/s, alloys can be obtained in the amorphous state for with intrinsic coercive of the order of 40–70 Oe. DSC analysis reveals that SmCo7 phase first precipitates from the amorphous matrix at 650C, followed by the crystallization of Sm2Co17 phase at 770C. Optimal coercivity of 7.98 kOe and remanent magnetization of 55.05 emu/g have been realized in magnet subjected to melt spinning at 40 m/s and annealing at 650C for 5 min. The domain structure of the annealed ribbon is composed of interaction domains typically 100–400 nm in size, which indicates the presence of a strong exchange coupling between the grains.