Nanostructured Core/Shell Powders for Magnets
Rare earths are naturally occurring minerals with unique magnetic properties that are used in electric vehicle (EV) motors and wind generators. Because these minerals are expensive and in limited supply, alternative technologies must be developed to replace rare-earth-based magnets in motors and generators. Alternatives to rare earths will contribute to the cost-effectiveness of EVs and wind generators, facilitating their widespread use and drastically reducing the amount of greenhouse gases released into the atmosphere.
Project Innovation + Advantages:
The Grid Logic team is adapting a form of vapor deposition technology to demonstrate a new approach to creating powerful hybrid magnets. This “physical vapor deposition particle encapsulation technology” utilizes an inert atmosphere chamber, which allows for precisely controlled and reproducible pressure, gas flow, and fluidization conditions for a powder vessel. The team will use this specialized chamber to fabricate nanostructured exchange-spring magnets, which require careful control of material dimension and composition. Nanostructured exchange-spring magnets are composite magnetic materials that use an exchange between soft magnetic materials, which have high saturation magnetization but are easily demagnetized, and hard magnetic materials that are difficult to demagnetize but have lower saturation magnetization and high coercivity. In this case, the team will create magnets consisting of Manganese Bismuth (MnBi) hard magnetic core particles with nanometer-scale Cobalt (Co) soft magnet shells. If successful, the team will demonstrate a process for producing: 1) A hard magnet core particle capable of withstanding a strong external magnetic field without becoming demagnetized; and 2) A soft magnet shell providing high magnetic saturation (i.e. maximum magnetization due to an external magnetic field). By combining precise control of nano-scale layering, material ratios, and material interfaces the project could develop a magnet that rivals permanent magnets made from rare earth elements. As an ARPA-E IDEAS project, this early stage research will provide proof of concept showing that the particle encapsulation system developed in this project can enable large-scale, cost-efficient production of composite magnets that do not require rare earth elements.