Combustion Driven Compaction of Nanostructured SmCo/Fe • Exchange spring magnetic materials can potentially increase the energy-products of permanent magnets • Powder consolidation has the ability to form composite magnets with arbitrary 3D shapes and sizes, less $ for expensive hard phase, possibility of mechanical fiber reinforcements
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Combustion Driven Compaction of Nanostructured SmCo/Fe
Combustion Driven Compaction of Nanostructured SmCo/Fe. Exchange spring magnetic materials can potentially increase the energy-products of permanent magnets - PowerPoint PPT Presentation
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Combustion Driven Compaction of Nanostructured SmCo/Fe
• Exchange spring magnetic materials can potentially increase the energy-products of permanent magnets
• Powder consolidation has the ability to form composite magnets with arbitrary 3D shapes and sizes, less $ for expensive hard phase, possibility of mechanical fiber reinforcements
Approach
• Obtain high coercivity by ball-milling hard phase
• Increase magnetization of the ball-milled hard phase by mixing with soft-phase
• Obtain exchange coupling between the hard and the soft phase by compaction
Hard
Soft
Hard/Soft
H
M
Challenges for compacted nanocomposites
• Preserve original phases during compaction
• Achieve strong coupling across interfaces
Here compare results for consolidation by three different methods: Hot Isostatic Pressing (HIP), Plasma Pressure Compaction (P2C), and Combustion Driven Compaction (CDC)
Powder Precursors
• Sm2Co17 (= Sm(Co0.67Fe0.234Cu0.07Zr0.024)7.5)* or SmCo5 for the hard phase [d ~ 1 m]
• High crystallinity acicular-Fe nanoparticles for soft phase [length ~ 200 nm, d ~ 20 nm]
• SmCo and Fe powder precursors were mixed together by gentle milling
[*Courtesy of C. Chen, Electron Energy Corporation]
[Courtesy of J. Nakano, Toda Corporation]
Acicular Fe Nanoparticles
• TEM of commercial acicular-Fe particles with an average length of 200 nm and average diameter of 20 nm
• Hydrogen reduction at 400 °C used to remove surface Fe3O4
Consolidation Methods
Plasma Pressure Compaction (P2C)
Compaction done at Materials Modification, Inc., 600°C, 45 MPa, 5 min
Hot Isostatic Pressing (HIP)
Compaction done at Wright-Patterson AFB 550°C, 21.6 MPa, 5 min