Advanced Magnetic Materials for Sensors, Power, and Multifunctional Applications: Developments in Soft Magnetic Materials
Sponsored by: TMS Functional Materials Division, TMS: Magnetic Materials Committee
Program Organizers: Daniel Salazar, BCMaterials; Alex Leary, NASA Glenn Research Center; Eric Theisen, Energy & Environmental Research Center; Huseyin Ucar, California Polytechnic University,Pomona; Yongmei Jin, Michigan Technological University

Wednesday 2:00 PM
March 2, 2022
Room: 213B
Location: Anaheim Convention Center

Session Chair: Alex Leary, NASA GRC


2:00 PM  Invited
Accelerated Design of Fe-based Soft Magnetic Materials Using Machine Learning and Stochastic Optimization: Raymundo Arroyave1; Yuhao Wang1; Tanner Kirk1; Yefan Tian1; Joseph Ross1; Ron Noebe2; 1Texas A&M University; 2NASA Glenn Research Center
    Machine learning was utilized to efficiently boost the development of soft magnetic materials. The design process includes building a database composed of published experimental results, applying machine learning methods on the database, identifying the trends of magnetic properties in soft magnetic materials, and accelerating the design of next-generation soft magnetic nanocrystalline materials through the use of numerical optimization. Machine learning regression models were trained to predict magnetic saturation (BS), coercivity (HC) and magnetostriction (λ), with a stochastic optimization framework being used to further optimize the corresponding magnetic properties. To verify the feasibility of the machine learning model, several optimized soft magnetic materials – specified in terms of compositions and thermomechanical treatments – have been predicted and then prepared and tested, showing good agreement between predictions and experiments, proving the reliability of the designed model.

2:30 PM  
Development of a CoFe - Al2O3 Soft Magnetic Composite Using Spark Plasma Sintering: Calvin Belcher1; Baolong Zheng1; Benjamin MacDonald1; Eric Langlois2; Benjamin Lehman2; Diran Apelian1; Todd Monson2; Enrique Lavernia3; 1University of California Irvine; 2Sandia National Laboratory; 3National Academy of Engineering
    For transformers and inductors to meet the world’s growing demand for electrical power, more efficient soft magnetic materials with high saturation magnetic polarization and high electrical resistivity are needed. This work studied the functional behavior of a soft magnetic composite synthesized via spark plasma sintering. CoFe powder particles coated with an insulating layer of Al2O3 were used as feedstock material to improve the electrical resistivity while retaining high saturation magnetic polarization. By maintaining a continuous non-magnetic Al2O3 phase throughout the material, both a high saturation magnetic polarization, above 1.5 T, and high electrical resistivity, above 100 μΩ*m, were achieved. Through microstructural characterization of samples consolidated at various temperatures, the role of microstructural evolution on the magnetic and electronic properties of the composite was elucidated. This study demonstrates the potential for large scale production of an efficient soft magnetic composite with high saturation magnetic polarization and electrical resistivity for transformer cores.

2:50 PM  
Domain Refined Amorphous Ribbon Technology for Core Loss Reduction: Eric Theisen1; 1Metglas Inc.
    Magnetic domain refining is a common technique to reduce core losses in high grades of Si-steel. Laser scribing and mechanical scribing are the most common methods to apply the domain refinement. Recently, these methods have been applied to amorphous ribbon and are currently available in the market. Here we look at how domain refinement improves the performance of high efficiency transformers cores and other common electrical power conversion products made from amorphous ribbon.

3:10 PM  
Two-step Annealing of FeNi-based Metal Amorphous Nanocomposites: Kevin Byerly1; Yuval Krimer1; Charudatta Phatak2; Eric Theisen3; Michael McHenry1; 1Carnegie Mellon University; 2Argonne National Laboratory; 3Metglas, Inc.
    A class of soft magnetic FeNi-based metal amorphous nanocomposite (MANC) alloys is investigated for their tunability of magnetic permeability through thermal-mechanical processing. Such FeNi-based alloys exhibit a response to external forces during the thermal annealing stage and enhanced mechanical properties as compared to FeSi-based alloys to allow for successful large-scale manufacturing. Here we demonstrate a technique to optimize magnetic properties in toroidal cores wound from flat strain annealed 25-mm wide ribbons of composition (Fe70Ni30)80Nb4Si2B14. A range of tensions from 25 – 250 MPa is applied as a function of ribbon length for a material speed 3.5 cm/s and annealing temperature 440 °C. Dramatic changes in magnetic properties are observed after winding and determined to be of magnetostrictive origin inclusive of casting curvature effects. A procedure to re-anneal the wound toroidal cores to reduce these detrimental effects is developed to optimally achieve core losses equivalent to state-of-the-art FINEMET MANC alloys.

3:30 PM Break

3:45 PM  
Flash Annealing of FeNi-based Metal Amorphous Nanocomposite: James Egbu1; Ahmed Talaat2; Kevin Byerly1; Paul Ohodnicki2; Michael McHenry1; 1Carnegie Mellon University; 2University of Pittsburgh
    Fe-based metal amorphous nanocomposite (MANC) alloys are an emerging class of soft magnetic materials that have shown to significantly lower core losses at high operating frequencies while maintaining high saturation induction and tunable permeability in high-speed motor applications. MANCs are produced by heat treating an amorphous metallic ribbon (AMR) to induce primary nanocrystallization. The nanocrystals that form provide high magnetic induction while an exchange coupled continuous amorphous phase provides high electrical resistivity. This work presents a comparison of the traditional conventional annealing process of AMR to a rapid annealing process by means of pre-heated Copper blocks that has been shown to enhance soft magnetic properties in amorphous and nanocrystalline materials. A systematic annealing study of (Fe70Ni30)80Nb4B14Si2 and (Fe70Ni30)85Nb0.5B14.5Si0 alloys and corresponding magnetic and structural characterizations results are presented in this work. We discuss magnetic properties in comparison with state of the art achieved for (Fe70Ni30)80Nb4B14Si2 using a two-step annealing process.

4:05 PM  
Radio Frequency Thermal Processing of Soft Magnetic Alloys: Ahmed Talaat1; David Greve2; Tyler Paplham1; Paul Ohodnicki1; 1University of Pittsburgh; 2DWGreve Consulting; Electrical &Computer Engineering, Carnegie Mellon University
    Microstructural engineering by means of electromagnetic radiation at extremely high heating and cooling rates can result in unique phase transformation pathways, including spatially selective thermal profiles, for example during partial crystallization in amorphous soft magnetic materials. In this work, we explore radio frequency (RF) induction heating of a range of different metallic alloy systems including bulk crystalline alloys as well as amorphous and nanocrystalline alloys. Simulations of electromagnetic heating effects through RF induction processing were carried out, including the impacts on microstructures and phase transformations. Simulation results were also compared with the results of experimental investigations. A comparison of different induction annealing approaches including longitudinal and transverse flux heating coil configurations, will be presented along with the results of structural and magnetic property characterization. The potential for leveraging RF induction annealing methods for enhanced performance of various types of soft magnetic components and devices will also be briefly discussed.

4:25 PM  
Investigation of Magnetic Behaviour of Spinel Ferrites using First Order Reversal Curves (FORC): Suraj Mullurkara1; Ahmed Talaat1; Brad Dodrill2; Paul Ohodnicki1; 1University of Pittsburgh; 2Lake Shore Cryotronics
    Transition metal spinel ferrites are known for unique magnetic properties which depend sensitively upon cation chemistry, site occupation, and microstructure. For example, the cobalt ferrites have been shown to undergo spinodal decomposition resulting in nano structuring at very fine length scales. The resultant magnetic properties have been shown to dependent on the degree of decomposition. MnZn-ferrites are preferred soft magnetic materials for power electronic applications over frequencies ranging from ~100 kHz to 5 MHz primarily due to their higher resistivities which results in the suppression of eddy current losses. However, in Mn-Zn ferrites hysteretic losses dominate under quasistatic and low frequency conditions, but can also play an important role under high frequency excitation. In this work, ferrite samples will be synthesized using standard powder processing techniques and characterized using XRD and SEM. Magnetization processes occurring in these materials will be investigated through vibrating sample magnetometry using major M-H loops and temperature dependant magnetization. In addition to major M-H loops, first order reversal curves (FORC) measurements will also be utilized to further elucidate dominant magnetization reversal mechanisms.