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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 37 records · Page 2
All sourcesNASA NTRSDOE OSTI
DOE OSTI2020

The transient properties of 2D magnets: from mechanical exfoliation to ultrafast optical spectroscopy of CrX 3 materials

The discovery of two-dimensional (2D) systems hosting intrinsic long-range magnetic order represents a seminal achievement, adding to the already diverse array of physics supported by layered van der Waals (vdW) materials. This finding has spurred great interest among the research community, with efforts aimed at uncovering their fundamental properties and light- matter interactions. A prototypical example of a 2D magnetic material is Crl 3 , where the strong relationship between crystalline structure and magnetic order, along with strong light- matter interactions, provide a promising platform to explore the nature of couplings between magnetism and the other degrees of freedom at the 2D limit. In this report, we highlight our efforts involving the use of time-resolved magneto-optical Kerr effect (TR-MOKE) spectroscopy to probe the magnetization and vibrational dynamics of Crl 3 . These measurements reveal evidence of strong exchange-mediated coupling between lattice vibrations and spin oscillations. Additionally, we discuss our related efforts to explore other material from the Chromium trihalide family through mechanical exfoliation to support subsequent optical spectroscopy investigations.

36 MATERIALS SCIENCE↗
DOE OSTI2024

MOLLER Spectrometer Magnet Design With Measured Mechanical Properties of Irradiated S2-Glass Reinforced Cyanate Ester Resin at Elevated Temperature

Here, the aim of this study was to retire the risk of maintaining the integrity of S2-glass reinforced CTD-403 (a cyanate ester resin) that is exposed to radiation and elevated temperature over the life of the measurement of a lepton–lepton electroweak reaction (MOLLER) experiment in experimental Hall A at Jefferson Lab, Newport News, VA. In this article, the shear strength and flexural modulus of irradiated S2-glass reinforced CTD-403 specimens were measured at 65 °C (the magnets are to operate at less than 65 °C) under two scenarios: vacuum and gaseous nitrogen. The testing method is the short-beam shear (SBS) test according to ASTM D2344. The specimens were exposed to neutrons and gamma rays up to 124 MGy. The results show that specimens have excellent resistance against radiation, only 23% degradation of apparent shear strength with 124 MGy at 65 °C under vacuum. At the highest dose areas of the coils, tungsten plates are used to reduce the radiation dose to the resin system. The conclusion is that S2-glass reinforced CTD-403 is well-suited for electrical insulation of MOLLER magnets.

36 MATERIALS SCIENCE↗
DOE OSTI2023

Development of dual phase soft magnetic laminate for advanced electric machines

The development of dual phase soft magnetic laminate for advanced electric machines at General Electric is summarized, including alloy development, properties, manufacturing trials, prototype experience, potential applications, and future material development. Dual phase soft magnetic laminates provide the flexibility to tune magnetic/non-magnetic state at the desired locations, using solution nitriding treatment with protective mask/coating. This enabling material technology benefits electric machine performance by reducing flux leakage in the laminates. It also decouples the electromagnetic and mechanical design, which opens up the design space for advanced electric machines. Magnetic and mechanical properties of dual phase laminates were compared to commercial FeSi and FeCo soft magnetic laminates. Driven by the market needs for high power density and high-speed electric machines, a synchronous reluctance (SynRel) machine without PMs using dual phase soft magnetic laminates was assessed in machine electromagnetic performance as well as rotor stress analysis by finite element simulation. Successful prototype build and testing further retired manufacturing risks and advanced the technology maturity level. Future material development with higher mechanical strength, higher saturation magnetization, higher permeability, and lower loss are highly desired for ground and air transportation electrification.

Rallabandi, Vandana↗
DOE OSTI2025

Multimodal Atomic Force Microscopy for the Characterization of Metallic Particulates

This study investigates the utility of multimodal, or functional, atomic force microscopy (AFM) for the characterization of individual particles and particle ensembles. In single-particle analyses, AFM imaging modes provided orthogonal insights into mechanical and magnetic properties that are not accessible through conventional electron microscopy. Although the experiments were inherently delicate and time-intensive, with an observed sample loss rate of approximately 30%, these techniques enabled the qualitative differentiation of grain structures and magnetic domains, underscoring the challenges of experimental robustness. For particle ensembles, AFM enabled the extraction of reliable 2D and 3D particle size distributions. However, efforts to chemically differentiate particles based on mechanical property contrasts were limited by scaling effects and the qualitative nature of the data. Overall, multimodal AFM offers valuable complementary information, but its application requires careful consideration of methodological limitations, particularly for sample integrity, calibration, and scalability of mechanical and magnetic measurements. This report is organized to first address the application of AFM to single-particle analysis using various imaging modalities, followed by its potential role in ensemble-level particle screening and differentiation.

36 MATERIALS SCIENCE↗
DOE OSTI2021

Development of High Bs Fe-Ni Based Metal Amorphous Nanocomposite by Optimization of Glass Forming Ability

A growing interest in electric vehicles challenges soft magnetic materials to improve efficiency and power density. Metal amorphous nanocomposites (MANCs) have lower coercivities and eddy current losses, allowing for greater efficiency and higher switching frequency. The later allows for high motor speeds and improved power density. However, commercially available and laboratory demonstrated MANCs have shortcomings. Fe-based MANCs, such as FINEMET have excellent magnetic properties, but mechanical properties limit their application in high speed electric motors (HSMs). Fe-Co based MANCs, such as HITPERM, have high saturation inductions and good mechanical properties, but elevated magnetostrictive losses. Co-based MANCs and more recent Fe-Ni based MANCs have low losses and good mechanical properties, but lower saturation inductions (1-1.2 T), that limit power density in HSMs. Recently, much work has explored improving saturation induction in MANCs by increasing the content of magnetic elements, which comes at the cost of glass-forming ability (GFA). These efforts where generally limited to trial and error testing. Additionally, all work to date has focused on Fe-based alloys. In this work, a method of using Thermocalc simulation to locate near-eutectic compositions has been applied to Fe-Ni based alloys. Minima in liquidus temperature and solidification range were found for a ternary composition range and used to identify compositions that retain good GFA as the percentage of magnetic elements is increased. The (Fe 70 Ni 30 ) x (B-Si-Nb) 100-x alloy system for x=82% and x=85% was explored by Thermocalc simulations. This is an increase in magnetic element content compared to previously developed x=80% alloys. 3 compositions in the x=82% system, and 1 alloy in the x=85% system where identified and successfully cast as amorphous ribbon. The amorphous nature of the ribbon was confirmed by a bend test and XRD. Magnetic testing was performed by PPMS to measure saturation induction and Curie temperature of the amorphous material. The Curie temperatures increased to 407-438 °C for the x=82% alloys, and 462 °C for the x=85% alloy. Saturation induction increased to 1.28-1.36 T for the x=82% alloy and 1.48 T for the x=85% alloy, which is a significant improvement over the ~370 °C Curie temperature and 1.2 T saturation of previous Fe-Ni alloy. Crystallization behavior was studied by XRD for the x=85% alloy, showing that crystallization process follows a 2-step process of Amorphous → BCC+FCC+Amorphous → BCC+FCC+Fe 3 B+Fe 23 B 6 . Post annealing magnetic properties were studied by strip testing, and saturation induction as high as 1.48 T was seen after optimal annealing. TEM was used to study structure of as cast and annealed material. 2 alloys with x=82% compositions were identified with an optimal crystalline size of 10-20 nm, while the x=85% alloy had this structure in the as cast state. This opens the possibility of using the alloy in the as cast state, without requiring annealing. In conclusion, alloys with good GFA and improved magnetic properties were identified by Thermocalc simulation.

Krimer, Yuval↗
DOE OSTI2020

Additive Manufacturing of Isotropic NdFeB PPS Bonded Permanent Magnets

Extrusion based additive manufacturing of polymer composite magnets can increase the solid loading volume fraction with greater mechanical force through the printing nozzle as compared to traditional injection molding process. About 63 vol% of isotropic NdFeB magnet powders were compounded with 37 vol% of polyphenylene sulfide and bonded permanent magnets were fabricated while using Big Area Additive Manufacturing without any degradation in magnetic properties. The polyphenylene sulfide bonded magnets have a tensile stress of 20 MPa, almost double than that of nylon bonded permanent magnets. Additively manufactured and surface-protective-resin coated bonded magnets meet the industrial stability criterion of up to 175 °C with a flux-loss of 2.35% over 1000 h. They also exhibit better corrosion resistance behavior when exposed to acidic (pH = 1.35) solution for 24 h and also annealed at 80 °C over 100 h (at 95% relative humidity) over without coated magnets. Thus, polyphenylene sulfide bonded, additively manufactured, protective resin coated bonded permanent magnets provide better thermal, mechanical, and magnetic properties.

36 MATERIALS SCIENCE↗
DOE OSTI2023

The Addition of Boron to Melt-Spun Fe-6.5%Si Ribbons

Fe-6.5%Si has higher electrical resistivity, lower magnetocrystalline anisotropy, and lower magnetostriction than traditional Fe-3.2%Si silicon steel. The reduced iron losses of Fe-6.5%Si render it a highly favorable candidate for high-speed motors and transformers. However, large-scale production of wide Fe-6.5%Si tape by rapid solidification can be challenging mainly because of its high melting point. In this work, boron is alloyed to Fe-6.5%Si to reduce its melting temperature and interfacial energy to improve the alloy’s processability. Boron additions from 0.01 wt.% to 2.24 wt.% into Fe-6.5%Si and its effect on ribbon thickness, grain size, magnetic, and mechanical properties were studied. Further, minor boron alloying significantly changed the melt pool stability and wetting on the quench wheel and in turn increased the quench rate with minimum impact on the magnetic saturation and ductility. Boron addition of < 0.06 wt.% was also found beneficial to the magnetic property of the alloy by lowering both its hysteresis and eddy current losses.

36 MATERIALS SCIENCE↗
DOE OSTI2023

A Review of the Mechanical Properties of Materials Used in Nb 3 Sn Magnets for Particle Accelerators

Superconducting magnets experience significant thermo-mechanical loads throughout their life cycle. These are introduced by the electro-magnetic forces during powering, but also by the prestress applied in many magnet designs. Further to this, the large thermal excursion that components of different materials experience can generate significant internal forces. The loads are also experienced by the superconducting coils, whose critical current can decrease as a consequence of the applied strain. It is then crucial to predict the overall mechanical behavior and conservatively design a magnet, avoiding failure of the mechanical components and of the superconducting coils. Finite Element Analysis (FEA) is generally used to perform these tasks, but its results rely heavily on the material properties and models used. This is in particular true for the coil composite, which is simplified to allow reasonable model sizes in full magnet models. Here we present the state-of-art knowledge of the mechanical properties of the materials mostly used in superconducting magnet construction. We review elastic and plastic properties at room and cryogenic temperature, thermal contraction, and summarize the state-of-art failure criteria for these materials. Finally, the paper summarizes the present understanding of the mechanical behavior and limits of Nb3Sn coils. For the first time, an orthotropic failure criteria is proposed.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
NASA NTRS1986

Investigation of the effects of cobalt ions on epoxy properties

The effects of Co(acac)sub x complexes on MY-720 epoxy properties have been investigated. It appears that Co2(+) ions form antibonding or nonbonding orbitals which increase the free volume and also reduce the cohesiveness of the host epoxy. The effects of Co2(+) ions, on the other hand, seem to result in increased Cohesiveness of the epoxy. The experimental values of magnetic moments of both types of ions in MY-720 suggest that the orbital momentum contributions of the (3d) electrons are partially conserved, though the effect is more pronounced for Co2(+) ions. The coordination environment of the cobalt ions in the host epoxy does not appear to be uniquely defined. These results indicate that the effects of metal ions on resin properties cannot be easily predicted on the basis of ligand field theory argument alone. Complex interactions between metal ions and host epoxy molecular structure suggest the desirability of parallel experimental investigations of electronic, magnetic, and mechanical properties of metal ion-containing epoxy samples for comparison with theory.

Singh, J. J.↗
NASA NTRS2010

Electrical Switching of Perovskite Thin-Film Resistors

Electronic devices that exploit electrical switching of physical properties of thin films of perovskite materials (especially colossal magnetoresistive materials) have been invented. Unlike some related prior devices, these devices function at room temperature and do not depend on externally applied magnetic fields. Devices of this type can be designed to function as sensors (exhibiting varying electrical resistance in response to varying temperature, magnetic field, electric field, and/or mechanical pressure) and as elements of electronic memories. The underlying principle is that the application of one or more short electrical pulse(s) can induce a reversible, irreversible, or partly reversible change in the electrical, thermal, mechanical, and magnetic properties of a thin perovskite film. The energy in the pulse must be large enough to induce the desired change but not so large as to destroy the film. Depending on the requirements of a specific application, the pulse(s) can have any of a large variety of waveforms (e.g., square, triangular, or sine) and be of positive, negative, or alternating polarity. In some applications, it could be necessary to use multiple pulses to induce successive incremental physical changes. In one class of applications, electrical pulses of suitable shapes, sizes, and polarities are applied to vary the detection sensitivities of sensors. Another class of applications arises in electronic circuits in which certain resistance values are required to be variable: Incorporating the affected resistors into devices of the present type makes it possible to control their resistances electrically over wide ranges, and the lifetimes of electrically variable resistors exceed those of conventional mechanically variable resistors. Another and potentially the most important class of applications is that of resistance-based nonvolatile-memory devices, such as a resistance random access memory (RRAM) described in the immediately following article, Electrically Variable Resistive Memory Devices (MFS-32511-1).

Liu, Shangqing↗
DOE OSTI2025

Metallic and ferromagnetic carbon allotrope discovered using molecular precursors

Although carbon materials are known for their versatile structures and properties, a crystalline phase of carbon being both metallic and ferromagnetic is yet to be found. Here, using an organic molecular precursor 3,3-dimethyl-1-butene ( C 6 H 12 ) and a comprehensive theoretical study, we have discovered a metastable crystalline carbon phase that is both metallic and ferromagnetic under ambient conditions. The new carbon structures, produced by stacking puckered layers of 4,6-membered rings, are found to exhibit exotic electronic, magnetic, and mechanical properties originating from a special s p 2 − s p 3 bonding topology. These findings open the prospect of realizing the metallic and ferromagnetic carbon allotrope in practice. Published by the American Physical Society 2025

Fang, Hong (ORCID:0000000209688687)↗
DOE OSTI2019

Binder jet additive manufacturing method to fabricate near net shape crack-free highly dense Fe-6.5 wt.% Si soft magnets

High silicon (Si) electrical steel has the potential for efficient use in applications such as electrical motors and generators with cost-effective in processing, but it is difficult to manufacture. Increasing the Si content beyond 3 wt.% improves magnetic and electrical properties, with 6.5 wt.% being achievable. The main goal of this research is to design, develop, and implement a scalable additive manufacturing process to fabricate Fe with 6.5 wt.% Si (Fe–6Si) steel with high magnetic permeability, high electrical resistivity, low coercivity, and low residual induction that other methods cannot achieve because of manufacturing limitations. Binder jet additive manufacturing was used to deposit near net shape components that were subsequently sintered via solid-state sintering to achieve near full densification. Here, it is shown that the use of solid-state sintering mitigates cracking since no rapid solidification occurs unlike fusion-based additive technologies. The Fe–6Si samples demonstrated an ultimate tensile strength of 434 MPa, electrical resistivity of 98 μΩ cm, and saturation magnetization of 1.83 T with low coercivity and high permeability. The results strongly supports to replace the only available 0.1 mm thick chemical vapor deposition (CVD) produced Si steel using the cost effective AM method with good mechanical and magnetic properties for motor ap

36 MATERIALS SCIENCE↗
DOE OSTI2021

3D printing of anisotropic Sm–Fe–N nylon bonded permanent magnets

Abstract Fabricating a bonded magnet with a near‐net shape in suitable thermoplastic polymer binders is of paramount importance in the development of cost‐effective energy technologies. In this work, anisotropic Sm 2 Fe 17 N 3 (Sm–Fe–N) bonded magnets are additively printed using SmFeN anisotropic magnetic particles in a polymeric binder polyamide‐12 (PA12). The anisotropic SmFeN bonded magnets are fabricated by Big Area Additive Manufacturing followed by post‐printing alignment in a magnetic field. Optimal post‐alignment results in an enhanced remanence of ∼0.68 T in PA12 reflected in a parallel‐oriented (aligned) measured direction. The maximum energy product achieved for the additively printed anisotropic bonded magnet of Sm–Fe–N in PA12 polymer is 78.8 KJ m −3 . Our results show advanced processing flexibility with 3D printing of the development of SmFeN nylon bonded magnets designed for applications with no critical rare earth magnets.

42 ENGINEERING↗
DOE OSTI2026

Mechanical characterization of Bi-2212 composite winding pack samples for high-field superconducting magnet design

Bi₂Sr₂CaCu₂O8−x (Bi-2212) multi-filament round wire is a high-temperature superconductor (HTS) capable of carrying high transport currents, which makes it suitable for high-field magnet applications. However, its weak Ag–Mg sheath leaves it vulnerable to mechanical stress, posing challenges for high-field magnet design. To better understand and improve mechanical stress management in Bi-2212 winding packs, we conducted an experimental study evaluating the axial stress–strain behavior of five winding pack configurations with varying insulation materials, reinforcement strategies, and construction quality. Using uniaxial tensile testing at 77 K, we measured Young’s modulus and Poisson’s ratio for each composition. Our results show that pure alumina braid insulation and co-wind reinforcements significantly enhance stiffness compared to aluminosilicate braids, with more than 2.5 times increased winding pack Young’s modulus. Rule of mixtures analysis further quantified the contribution of non-wire composite components to overall stiffness. These findings highlight the critical role of insulation material selection and reinforcement design in optimizing Bi-2212 coil performance under stress, providing a foundation for improved mechanical models and more reliable high-field HTS magnet designs.

Bi-2212 magnet↗
DOE OSTI2019

Dynamics and manipulation of ferroelectric domain walls in bismuth ferrite thin films

Abstract Ferroelectric domain walls differ from domains not only in their crystalline and discrete symmetry, but also in their electronic, magnetic, and mechanical properties. Although domain walls provide a degree of freedom to regulate the physical properties at the nanoscale, the relatively lower controllability prevents their practical applications in nano-devices. In this work, with the advantages of 3D domain configuration detection based on piezoresponse force microscopy, we find that the mobility of three types of domain walls (tail-to-tail, head-to-tail, head-to-head) in (001) BiFeO3 films varies with the applied electrical field. Under low voltages, head-to-tail domain walls are more mobile than other domain walls, while, under high voltages, tail-to-tail domain walls become rather active and possess relatively long average lengths. This is due to the high nucleation energy and relatively low growth energy for charged domain walls. Finally, we demonstrate the manipulation of domain walls through successive electric writings, resulting in well-aligned conduction paths as designed, paving the way for their application in advanced spintronic, memory and communication nano-devices.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
NASA NTRS1981

Altered basaltic glass - A terrestrial analog to the soil of Mars

In order to understand the nature of weathering processes and the formation of clay-like substances on Mars, analogous terrestrial processes and materials have been examined including sideromelane and palagonite. It is shown that palagonite is a good analog to the soil of Mars to the level of precision available from Viking and ground-based telescopic spectral measurements. Points of resemblance between the two materials include bulk chemical composition, particle size, reflectance spectra, and magnetic properties. A mechanism for the formation of Martian soil, based on a palagonite model, is proposed.

Allen, C. C.↗
NASA NTRS2023

The Impact of Soft Magnetic Materials in Electrified Aircraft Applications

Electrical systems with high power and high power density are integral to many aerospace and energy applications. These systems, enabled by power electronics with wide bandgap semiconductor devices, require management of both efficiency/thermal aspects and electromagnetic interference that are problems specific to high power and high frequency applications, respectively. In addition to advanced active components, these applications also require passive components (inductors, capacitors, conductors) capable of operation under challenging conditions. This work surveys the state of the art of magnetic components and soft magnetic materials used as inductive cores. The wide variety of motor and converter topologies translates to a variety of requirements in the magnetics including mechanical properties, permeabilities, and frequency response. The scaling impact of material properties will be surveyed with respect to component performance and sizing, using both data from experiment and the published literature. Variations on simulations, both in lumped circuits and finite element models, will also be discussed as these are important aspects of the design phase of modern power electronics.

Alex Leary↗