Magnetics and the Critical Materials Challenge: An FMD Symposium Honoring Matthew J. Kramer: Hard Magnets
Sponsored by: TMS Functional Materials Division, TMS: Magnetic Materials Committee
Program Organizers: Scott McCall, Lawrence Livermore National Laboratory; Ryan Ott, Ames Laboratory

Monday 8:30 AM
February 28, 2022
Room: 210D
Location: Anaheim Convention Center

Session Chair: Ryan Ott, Ames Laboratory


8:30 AM Introductory Comments

8:35 AM  Invited
Challenges in Affordable, Reliable Permanent Magnets: Matthew Kramer1; 1Iowa State University
    Increasing global efforts to reduce CO2 is putting additional demand on high performance permanent magnets (PM) for efficient renewable energy generation and electrification of transportation. Demand for PM for these applications, and rare earths elements (REE) used to make them, is expected to double by 2030. Reducing supply chain criticality for REE, especially heavy REEs (HREE), is a multifaceted challenge. Improved processing can minimize and even eliminate the HREE in 2-14-1 based compounds in most applications, but can this be done economically? Increased utilization of Ce and La can reduce supply chain criticality of Nd and Pr but can this be achieved without sacrificing performance, in particular, without Co, a critical element? Can lower cost PM using non-critical elements fill in the gap for moderate performance PM lowering overall demand for higher performance PM? This talk will touch on these challenges and the processing-property relationships for improving remanence and coercivity.

9:05 AM  Invited
Iron Nitride: a Non-rare-earth Containing Permanent Magnet: Frank Johnson1; 1Niron Magnetics, Inc.
    Niron Magnetics, Inc. is commercializing Iron Nitride, a high performance, completely rare earth free permanent magnet technology. Iron Nitride will act as an economical substitute for several grades of both sintered and bonded NdFeB magnets. Niron’s Iron Nitride technology is based on progress achieved by the University of Minnesota under work supported by the Department of Energy’s Rare Earth Alternatives in Critical Technologies ARPA-E REACT program. These magnets are based on the α”-Fe16N2 compound which has high saturation magnetization and a moderate magnetocrystalline anisotropy due to a tetragonal crystal structure. Iron Nitride is manufactured from low-cost, non-critical elemental components. The unique characteristics of Iron Nitride include a magnetic strength higher than most grades of NdFeB permanent magnets. Test data also indicates that iron nitride exhibits superior temperature stability when compared to NdFeB. Niron’s magnets are positioned to substitute for NdFeB in applications such as motors with high torque output.

9:35 AM  Invited
Critical Materials Challenges in ThMn12-type Hard Magnetic Alloys for Permanent Magnets: Daniel Salazar1; 1BCMaterials
    The great performance of commercial high-energy permanent magnets is strongly dependent on the use of critical and strategic raw materials, such as Dy and Tb, which provide enhanced coercivity and increased thermal stability. To overcome this dependency on scarce materials, worldwide efforts to develop rare-earth lean/free permanent magnets are promoted. ThMn12-type hard magnetic phases are promising candidates due to their high saturation magnetization, Curie point and anisotropy field; these properties are enhanced by the addition of light elements (H, N) at the interstitial sites of the 1:12 crystal structure or by Sm-substitution at the Th site. Progress in the development of coercivity on samples with high anisotropy has been done using different processing methods and the intrinsic properties of the hard-magnetic phases were significantly improved by the proposed techniques. The maximum coercivity reached in these compounds is above 0.6T and 1T in nitride Nd-based and Sm-based 1:12 alloys, respectively.

10:05 AM Break

10:25 AM  Invited
Developing Substitutes for Magnetic Alloys: Thomas Lograsso1; 1Critical Materials Institute
    The search for alternative alloys and in particular magnetic alloys necessarily involves an integrated computational/experimental approach. Machine learning can accelerate the identification of potential substitutes, those that have sufficient intrinsic properties, but real candidates are determined by extrinsic properties arising from microstructural features developed via thermomechanical processing. Two examples of materials substitution, driven by the desire to reduce critical rare earth content will be discussed. The first example is the development of galfenol, a magnetostrictive alloy to replace terfenol-D which contains high amounts of both Tb and Dy. The second example is CeCoCuFe-based permanent magnets developed in the Critical Materials Institute (CMI). CMI focuses on reducing Nd or Sm through replacement with La or Ce, while maximizing Fe use and minimizing cobalt. Unlike other RE-based magnets, the microstructural aspects responsible for coercivity in this alloy are unique and required careful electron microscopy to identify the origins.

10:55 AM  Invited
Controlling First-order Magnetic Phase Transitions in Rare-earth Intermetallics: Vitalij Pecharsky1; 1Ames Laboratory, Iowa State University
     First-order magnetostructural phase transitions are highly sought in the development of functional magnetic materials, for example those that exhibit giant magnetocaloric effects. Understanding the mechanisms that lead to magnetic and lattice instabilities is important both to achieve a more complete control of magnetostructural phase transformations and for design of better materials in support of future energy applications. We compare Eu2In and Pr2In that exhibit anhysteretic magnetoelastic phase transitions and fully-reversible giant magnetocaloric effects. We also discuss novel approaches for controlling hysteresis in Gd5Si2Ge2 and La(Fe,Si)13 – archetypal materials that exhibit partially reversible giant magnetocaloric effects.This work was performed at the Ames Laboratory with support by the Division of Materials Sciences and Engineering of the Office of Basic Energy Sciences, Office of Science of U.S. Department of Energy (DOE). Ames Laboratory is operated for the U.S. DOE by Iowa State University of Science and Technology under Contract No. DE-AC02-07CH11358.