Rapidly Solidified Sm–Co–V Nanocomposite Permanent Magnets

Authors

R. S. K. Valiveti, University of Nebraska - Lincoln
A. Ingmire, University of Nebraska - Lincoln
Jeffrey E. Shield, University of Nebraska - LincolnFollow

Date of this Version

2009

Comments

Published in JOURNAL OF APPLIED PHYSICS 105, 07A727 (2009). Copyright © 2009 American Institute of Physics. Used by permission.

Abstract

Alloys around the Sm–Co eutectic composition provide an opportunity to form two-phase nanocomposite permanent magnets consisting of nanoscale Co fibers embedded in Sm₂Co₁₇.While ternary alloying elements may refine the scale of the structure, they may also disrupt the eutectic growth and lead to the formation of primary Co. Thus, microstructural selection maps were constructed for conventionally solidified Sm–Co–V alloys. It was found that V additions enlarged the primary Sm₂Co₁₇-forming region and, at (Sm_0.09Co_0.91)₉₇ V₃, resulted in a eutectic structure. Upon rapid solidification, this alloy was determined to have a coercivity of 5 kOe with a high remanent ratio. However, the V addition reduced the magnetization, which limited the energy product to 4.3 MG Oe. The rapidly solidified structure consisted of primary SmCo₇ dendrites along with an intergranular Co region, suggesting that eutectic structure formation is skewed by underlying metastable phase relationships.