|About this Abstract
||2016 TMS Annual Meeting & Exhibition
||Advanced Magnetic Materials: An FMD Symposium in Honor of Michael E. McHenry
||Co-based Rare Earth Free Permanent Magnet Materials
||Meiyu Wang, Michael Lucis, Jeff Shield
|On-Site Speaker (Planned)
The Co-Zr and Co-Hf systems both contain compounds with intrinsic properties attractive for permanent magnet materials. Both Zr2Co11 and HfCo7 have reasonably high magnetocrystalline anisotropies and high magnetization. For both compounds, the appropriate structures are best accessed using rapid solidification processing, although different cooling rates result in different phase formation. The high cooling rate by-passes or minimizes peritectic regions and stabilizes high-temperature phases. For Zr2Co11, polymorphism exists, and different solidification rates influence the stabilization of the hard magnetic structure. Also, phase decomposition occurs at heat treatment temperatures as low as 600°C. In Hf-Co, the solidification rate significantly impacts phase formation, as the phase diagram is altered due to the non-equilibrium processing. Hcp Co is observed both inter- and intragranularly, the former forming during solidification and the latter during precipitation during cooling. The precipitated Co forms as laths and creates an excellent exchange-coupled system due to the scale.
||Planned: None Selected