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Feedstock and Heterogeneous Structure for Tough Rare Earth Permanent Magnets and Production Process Thereof
Category(s):
For Information, Contact:
Craig Forney
Commercialization Manager, Chemistry and Materials Sciences
515-294-4740
licensing@iastate.edu
Web Published:
2/21/2018
ISURF #
4673
Summary:
Iowa State University and Ames Laboratory researchers have developed a method for producing rare earth permanent magnets (REPMs) that reduces their susceptibility to breakage. The process involves unitizing a bimodal or multimodal size distribution of powders in isostatic pressing, which minimizes crack propagation along the grain boundaries of the magnet. This invention significantly enhanced flexural strength and fracture toughness while maintaining the hard magnetic properties.

Development Stage:
Description:
Among three basic classes of permanent magnets, sintered magnets, bonded magnets and additive manufacturing, the sintered magnets are the highest performing. Sintered magnets produce up to twice the magnetic field strength of bonded magnets and have an energy density up to four times higher. However, one of the weakness of sintered magnets is their brittleness, as they easily crack, particularly during machining or as a results of external stress.

Iowa State University and Ames Laboratory researchers have demonstrated enhanced toughness and improved magnetic performance by producing novel tough REPMs with heterogeneous structures, such as bi-modal, tri-modal, multi-modal or gradient grained structures, or other microstructural heterogeneity. This invention not only improves the magnet manufacturing efficiency and machinability, it reduces part failure rate, and effectively uses expensive critical materials. It also greatly expands the market for this class of permanent magnets. Tougher and fracture resistant magnets offer opportunities for new applications, new shapes, and lower costs. Tougher REPMs also make it possible for production of bulky magnets with even higher magnetic performance and larger dimensions via optimization of alloy composition and heat treatment process.

Advantage:
• Enhanced toughness and improved magnetic performance
• Effective use of expensive critical materials
• Improved the magnet manufacturing efficiency and machinability
• Increased resistance to chipping in machining, reducing part failure rate
• Simple technology to integrate into production

Application:
Improved mechanical properties for sintered REPMs, with the potential to enable new applications, new shapes, and lower costs for sintered magnets.
Patent Information:
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