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At least 145 records · Page 8
All sourcesNASA NTRSDOE OSTI
DOE OSTI2023

NdFeB Permanent Magnet Uses, Projected Growth Rates and Nd Plus Dy Demands across End-Use Sectors through 2050: A Review

Rare earth element (REE) permanent magnets (NdFeB) are a critical element in a vast and growing number of industrial applications. In consumer electronics, a broad category encompassing computer, CD, and DVD hard drives, in addition to the ubiquitous cell phones, the nominal NdFeB magnet content may be small, but the global market share for this sector accounts for almost 30% of NdFeB demand, due to a large and continually increasing consumer base. It is estimated that wind turbines that primarily employ permanent magnets will add roughly 110 GW annually of on- and off-shore capability over the next few years. Electric vehicles (EVs) and E-bicycles (EBs) equipped with permanent magnet motors comprise the transportation contribution. Permanent magnet motors have garnered nearly 100% of the market share among EV manufacturers worldwide. Industrial, professional service, and personal robots, most using permanent magnets, are also included in the projected global need for rare earths, particularly Nd and Dy. The sector projects significant growth of approximately 10% across robotic categories. In this paper, we calculate the future demand for Nd and Dy through 2050 across these sectors using a compounded annual growth rate coupled with magnet weight and rare earth content. Uncertainties in the estimates, such as the true global production of Nd, a range of end-product scales and/or unit types in each sector, varied magnet compositions, and the variety of uses within a sector, are all considered.

Geochemistry & Geophysics↗
NASA NTRS1991

Room temperature Dy:YLF laser operation at 4.34 micron

A Dy:YLF laser operating on the 6H11/2 to 6H13/2 transition at 4.34 micron and using a laser pumping scheme is reported. This pumping scheme is necessitated by the short upper-laser-level lifetime and the small effective stimulated-emission cross section. A suitable laser for this application is the Er:YLF laser operating at 1.73 micron. A simple model that approximates Dy:YLF laser performance well is presented. Results on laser performance, including a determination of the slope efficiency and threshold as a function of the output mirror reflectivity and a correlation of the pulse length with the laser output energy, are reported. Overall laser efficiency is found to be limited primarily by the ratio of the pump wavelength to laser output wavelength and the terminated four-level laser operation. Spectroscopic results, including the measurement of the absorption spectra and the lifetimes of both the upper- and lower-laser manifolds, are given.

Barnes, Norman P.↗
DOE OSTI2020

Materials Data on Dy(CrSi)2 by Materials Project

DyCr2Si2 crystallizes in the tetragonal I4/mmm space group. The structure is three-dimensional. Dy3+ is bonded in a body-centered cubic geometry to eight equivalent Si4- atoms. All Dy–Si bond lengths are 2.99 Å. Cr+2.50+ is bonded to four equivalent Si4- atoms to form a mixture of edge and corner-sharing CrSi4 tetrahedra. All Cr–Si bond lengths are 2.40 Å. Si4- is bonded in a 9-coordinate geometry to four equivalent Dy3+, four equivalent Cr+2.50+, and one Si4- atom. The Si–Si bond length is 2.47 Å.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Dy(CuSi)2 by Materials Project

DyCu2Si2 crystallizes in the tetragonal I4/mmm space group. The structure is three-dimensional. Dy3+ is bonded in a distorted body-centered cubic geometry to eight equivalent Si4- atoms. All Dy–Si bond lengths are 3.05 Å. Cu+2.50+ is bonded to four equivalent Si4- atoms to form a mixture of corner and edge-sharing CuSi4 tetrahedra. All Cu–Si bond lengths are 2.38 Å. Si4- is bonded in a 9-coordinate geometry to four equivalent Dy3+, four equivalent Cu+2.50+, and one Si4- atom. The Si–Si bond length is 2.35 Å.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Dy(SiRu)2 by Materials Project

DyRu2Si2 crystallizes in the tetragonal I4/mmm space group. The structure is three-dimensional. Dy3+ is bonded in a 8-coordinate geometry to eight equivalent Si4- atoms. All Dy–Si bond lengths are 3.22 Å. Ru+2.50+ is bonded to four equivalent Si4- atoms to form a mixture of corner and edge-sharing RuSi4 tetrahedra. All Ru–Si bond lengths are 2.38 Å. Si4- is bonded in a 4-coordinate geometry to four equivalent Dy3+ and four equivalent Ru+2.50+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Dy(SiNi)2 by Materials Project

DyNi2Si2 crystallizes in the tetragonal I4/mmm space group. The structure is three-dimensional. Dy3+ is bonded in a distorted body-centered cubic geometry to eight equivalent Si4- atoms. All Dy–Si bond lengths are 3.05 Å. Ni+2.50+ is bonded to four equivalent Si4- atoms to form a mixture of edge and corner-sharing NiSi4 tetrahedra. All Ni–Si bond lengths are 2.30 Å. Si4- is bonded in a 9-coordinate geometry to four equivalent Dy3+, four equivalent Ni+2.50+, and one Si4- atom. The Si–Si bond length is 2.41 Å.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Dy(FeSi)2 by Materials Project

DyFe2Si2 crystallizes in the tetragonal I4/mmm space group. The structure is three-dimensional. Dy3+ is bonded in a distorted body-centered cubic geometry to eight equivalent Si4- atoms. All Dy–Si bond lengths are 3.08 Å. Fe+2.50+ is bonded to four equivalent Si4- atoms to form a mixture of corner and edge-sharing FeSi4 tetrahedra. All Fe–Si bond lengths are 2.27 Å. Si4- is bonded in a 9-coordinate geometry to four equivalent Dy3+, four equivalent Fe+2.50+, and one Si4- atom. The Si–Si bond length is 2.56 Å.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Dy(MnSi)2 by Materials Project

DyMn2Si2 crystallizes in the tetragonal I4/mmm space group. The structure is three-dimensional. Dy3+ is bonded in a body-centered cubic geometry to eight equivalent Si4- atoms. All Dy–Si bond lengths are 3.02 Å. Mn+2.50+ is bonded to four equivalent Si4- atoms to form a mixture of edge and corner-sharing MnSi4 tetrahedra. All Mn–Si bond lengths are 2.36 Å. Si4- is bonded in a 9-coordinate geometry to four equivalent Dy3+, four equivalent Mn+2.50+, and one Si4- atom. The Si–Si bond length is 2.48 Å.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Dy(CoB)2 by Materials Project

DyCo2B2 crystallizes in the tetragonal I4/mmm space group. The structure is three-dimensional. Dy3+ is bonded in a body-centered cubic geometry to eight equivalent B3- atoms. All Dy–B bond lengths are 2.88 Å. Co+1.50+ is bonded to four equivalent B3- atoms to form a mixture of distorted edge and corner-sharing CoB4 tetrahedra. All Co–B bond lengths are 2.00 Å. B3- is bonded in a 4-coordinate geometry to four equivalent Dy3+ and four equivalent Co+1.50+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Dy(NiP)2 by Materials Project

DyNi2P2 crystallizes in the tetragonal I4/mmm space group. The structure is three-dimensional. Dy3+ is bonded in a distorted body-centered cubic geometry to eight equivalent P3- atoms. All Dy–P bond lengths are 2.97 Å. Ni+1.50+ is bonded to four equivalent P3- atoms to form a mixture of edge and corner-sharing NiP4 tetrahedra. All Ni–P bond lengths are 2.27 Å. P3- is bonded in a 9-coordinate geometry to four equivalent Dy3+, four equivalent Ni+1.50+, and one P3- atom. The P–P bond length is 2.31 Å.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Dy(CoSi)2 by Materials Project

DyCo2Si2 crystallizes in the tetragonal I4/mmm space group. The structure is three-dimensional. Dy3+ is bonded in a distorted body-centered cubic geometry to eight equivalent Si4- atoms. All Dy–Si bond lengths are 3.01 Å. Co+2.50+ is bonded to four equivalent Si4- atoms to form a mixture of corner and edge-sharing CoSi4 tetrahedra. All Co–Si bond lengths are 2.27 Å. Si4- is bonded in a 9-coordinate geometry to four equivalent Dy3+, four equivalent Co+2.50+, and one Si4- atom. The Si–Si bond length is 2.50 Å.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Dy(Mo3S4)2 by Materials Project

DyMo6S8 crystallizes in the trigonal R-3 space group. The structure is three-dimensional. Dy3+ is bonded in a body-centered cubic geometry to eight S2- atoms. There are two shorter (2.71 Å) and six longer (3.00 Å) Dy–S bond lengths. Mo+2.17+ is bonded to five S2- atoms to form a mixture of edge and corner-sharing MoS5 square pyramids. There are a spread of Mo–S bond distances ranging from 2.42–2.59 Å. There are two inequivalent S2- sites. In the first S2- site, S2- is bonded in a 1-coordinate geometry to one Dy3+ and three equivalent Mo+2.17+ atoms. In the second S2- site, S2- is bonded in a 5-coordinate geometry to one Dy3+ and four equivalent Mo+2.17+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Dy(SiAg)2 by Materials Project

DyAg2Si2 crystallizes in the tetragonal I4/mmm space group. The structure is three-dimensional. Dy3+ is bonded to eight equivalent Si4- atoms to form DySi8 hexagonal bipyramids that share corners with sixteen equivalent AgSi4 tetrahedra, edges with four equivalent DySi8 hexagonal bipyramids, edges with eight equivalent AgSi4 tetrahedra, and faces with four equivalent DySi8 hexagonal bipyramids. All Dy–Si bond lengths are 3.15 Å. Ag+2.50+ is bonded to four equivalent Si4- atoms to form AgSi4 tetrahedra that share corners with eight equivalent DySi8 hexagonal bipyramids, corners with four equivalent AgSi4 tetrahedra, edges with four equivalent DySi8 hexagonal bipyramids, and edges with four equivalent AgSi4 tetrahedra. All Ag–Si bond lengths are 2.60 Å. Si4- is bonded in a 9-coordinate geometry to four equivalent Dy3+, four equivalent Ag+2.50+, and one Si4- atom. The Si–Si bond length is 2.29 Å.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Dy(InPt)4 by Materials Project

DyPt4In4 crystallizes in the hexagonal P6_3/mmc space group. The structure is three-dimensional. Dy3+ is bonded in a 8-coordinate geometry to eight Pt2- atoms. There are six shorter (3.01 Å) and two longer (3.14 Å) Dy–Pt bond lengths. There are two inequivalent Pt2- sites. In the first Pt2- site, Pt2- is bonded in a distorted body-centered cubic geometry to one Dy3+ and seven In+1.25+ atoms. There are a spread of Pt–In bond distances ranging from 2.76–2.88 Å. In the second Pt2- site, Pt2- is bonded in a 8-coordinate geometry to three equivalent Dy3+ and four In+1.25+ atoms. There are three shorter (2.78 Å) and one longer (2.82 Å) Pt–In bond lengths. There are two inequivalent In+1.25+ sites. In the first In+1.25+ site, In+1.25+ is bonded in a distorted pentagonal planar geometry to five Pt2- atoms. In the second In+1.25+ site, In+1.25+ is bonded in a distorted hexagonal planar geometry to six Pt2- atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2025

Microstructure refinement of hot deformed Dy-free NdFeB magnets through a novel cold sintering approach by pressure-assisted spark plasma sintering

Anisotropic fine-grained Dy-free NdFeB high-performance magnets were produced using a novel cold sintering approach by pressure-assisted spark plasma sintering (SPS). The NdFeB nanocrystalline ribbon powders were subjected to cold sintering below 450 °C using pressure-assisted SPS, followed by hot deformation at 710 °C and 810 °C via SPS. Results indicate that cold sintering below 450 °C effectively restricts grain growth in the NdFeB magnets, yielding sub-100 nm scale grains across both fine-grained regions and most coarse-grained regions. The refined grain structure achieved through cold sintering allows for a lower hot deformation temperature as compared with the magnet by conventional sintering, as finer grains allow easier deformation and grain sliding/rotation. This process produces a highly fine-grained and anisotropic microstructure to achieve high magnetic performance (i.e., high intrinsic coercivity, remanence, and maximum energy product) in the magnets. The cold sintering (at 350 °C) and lower hot deformation temperatures required (e.g., 710 °C) help control grain coarsening and limit grain size that is commensurate with the size of a single magnetic domain of the Nd 2 Fe 14 B magnetic matrix phase, resulting in high intrinsic coercivity (H ci =11.4 kOe). Furthermore, the reduced hot deformation temperature mitigates the formation of coarse grain bands, leading to improved magnetic properties, specifically an increased remanence (B r = 14.3 kGs) and a high maximum energy product ((BH) max = 48 MGOe). In conclusion, cold sintered hot deformed NdFeB magnet also shows good thermal stability with reversible temperature coefficient α(B r )= -0.097 %/K and α(H ci )= -0.616 %/K at elevated temperatures up to 400 K.

Cold Sintering↗
DOE OSTI2024

Tailored (La 0.2 Pr 0.2 Nd 0.2 Tb 0.2 Dy 0.2 ) 2 Ce 2 O 7 as a Highly Active and Stable Nanocatalyst for the Oxygen Evolution Reaction

Abstract Designing highly active and robust catalysts for the oxygen evolution reaction is key to improving the overall efficiency of the water splitting reaction. It has been previously demonstrated that evaporation induced self‐assembly (EISA) can be used to synthesize highly porous and high surface area cerate‐based fluorite nanocatalysts, and that substitution of Ce with 50% rare earth (RE) cations significantly improves electrocatalyst activity. Herein, the defect structure of the best performing nanocatalyst in the series are further explored, Nd 2 Ce 2 O 7 , with a combination of neutron diffraction and neutron pair distribution function analysis. It is found that Nd 3 + cation substitution for Ce in the CeO 2 fluorite lattice introduces higher levels of oxygen Frenkel defects and induces a partially reduced RE 1.5 Ce 1.5 O 5 +x phase with oxygen vacancy ordering. Significantly, it is demonstrated that the concentration of oxygen Frenkel defects and improved electrocatalytic activity can be further enhanced by increasing the compositional complexity (number of RE cations involved) in the substitution. The resulting novel compositionally‐complex fluorite– (La 0.2 Pr 0.2 Nd 0.2 Tb 0.2 Dy 0.2 ) 2 Ce 2 O 7 is shown to display a low OER overpotential of 210 mV at a current density of 10 mAcm −2 in 1M KOH, and excellent cycling stability. It is suggested that increasing the compositional complexity of fluorite nanocatalysts expands the ability to tailor catalyst design.

Chemistry↗
DOE OSTI2025

Interstitial Atoms and the Frustrated and Allowed Structural Transitions Principle: Tunability in the Electronic Structure of AuCu 3 ‐type Frameworks in Dy 4 T 1− x Ga 12 (T = Ag, Ir)

In this Article, we explore how the chemical pressure (CP) features of an intermetallic phase may provide opportunities to couple perturbations in electron count with the stabilization of the underlying geometrical structure. AuCu 3 ‐type LnGa 3 (Ln = lanthanide or group 3 metal) phases contain octahedral cavities of negative CP held open by overly compressed Ln–Ga interactions, leading to a series of transition metal‐stuffed derivatives. We present new additions to this family with the synthesis and crystal structures of Dy 4 T 1−x Ga 12 with (T, x) = (Ag, 0.29) and (Ir, 0.15), adopting Y 4 PdGa 12 ‐type superstructures of the AuCu 3 ‐type. density functional Ttheory (DFT)‐CP calculations, when adjusted to avoid dipolar CP features, affirm that T atom incorporation provides a mechanism for the relief of packing tensions, while electronic density of states distributions illustrate that the T atoms serve largely as electron or hole donors to the band structure, as needed for them to attain d 10 configurations. The maximum obtainable value for x may be limited by a mismatch between the Fermi energy and pseudogap, in line with the balance of factors envisioned by the frustrated and allowed structural transitions principle. Furthermore, trends in resistivity measurements on T = Ir, Pd, and Ag compounds are interpretable in terms of the varying degrees of disorder arising from x < 1.0.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2023

Temperature and anion ligand field dependence of LnCl 3 (Ln = Nd, Dy, Sm) electronic absorption spectra in LiCl–KCl eutectic molten salt

A comprehensive knowledge of the coordination, bonding, and speciation of elements in molten salt mixtures is necessary to understand and predict the chemical and physical properties of the salt. Absorption spectroscopy can yield information about the chemistry of species of interest in alkali halide molten salt mixtures by revealing information about the electronic structure and transitions of those species. In this study, ultraviolet (UV), visible (vis), and near-infrared (NIR) absorption spectroscopy was used to examine changes to the electronic structure of trivalent Nd, Sm, and Dy in LiCl–KCl eutectic molten salt with changes in temperature and the anion composition of the melt. With increasing temperature, changes to spectral features suggest a distortion of the coordination complexes. Changes to lineshape with the substitution of alternative halide anions were examined and analyzed, revealing differences in the coordination for I – versus F – with the lanthanides. Gaussian peak fitting was used to show that the changes in lineshape with the progressive addition of F – anions can be explained by the superposition of a set of absorption bands from complexes with all Cl – anion ligands and a set of blueshifted absorption bands from complexes containing both F – and Cl – anion ligands. Finally, this work yields a new method to analyze and interpret change to electronic absorption spectra for f-block elements dissolved in alkali halide molten salts as well as new observations of the interactions of larger and smaller halide anions with lanthanides in Cl – -based molten salts.

38 RADIATION CHEMISTRY, RADIOCHEMISTRY, AND NUCLEA↗