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At least 217 records · Page 12
All sourcesNASA NTRSDOE OSTI
DOE OSTI2024

Microstructural and Oxidation Effects of Nb Additions to U3Si2

U3Si2 is a long term, accident-tolerant nuclear fuel candidate for light-water reactors because of its superior thermal conductivity and increased uranium density when compared to traditional uranium dioxide (UO2). While reducing internal thermal stresses and increasing efficiency, U3Si2 exhibits energetic oxidation during certain off-normal and accident scenarios, which include coolant or steam exposure. To mitigate this, Nb is investigated as an alloy constituent to enhance corrosion resistance and increase mechanical strength. The work presented investigates the response of Nb-alloyed U3Si2 to steam atmospheres. A thermogravimetric analysis is conducted in flowing steam to T > 1000 °C to assess oxidation resistance. The phase characterization of as-melted, thermally annealed and post-oxidation compositions with up to 12 vol% Nb by powder X-ray diffraction, scanning electron microscopy, and energy dispersive spectroscopy is reported.

11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗
DOE OSTI2022

Development and demonstration of next generation technology for Nb_3Sn accelerator magnets with lower cost, improved performance uniformity, and higher operating point in the 12-14 T range

The scope of the proposal outlined in this white paper is the development and demonstration of the technology needed for next generation of Nb_3Sn accelerator magnets in the 12-14 T range. The main goal is to cut magnet cold-mass cost by a factor 2 or higher with respect to the Nb_3Sn magnets produced by the US Accelerator Upgrade Project (AUP) for the High-Luminosity Large Hadron Collider (HL-LHC). This goal will be achieved by significant reduction of labor hours, higher operating point, and improved performance uniformity. A key factor will be automation that will be achieved through industry involvement and benefitting from the experience gained in US national laboratories through the production of the AUP magnets. This partnership will enable the development of a technology that will be easily transferable to industry for mid- and large-scale production of Nb_3Sn accelerator magnets in the 12-14 T range. This step is essential to enable next generation of colliders such as the FNAL-proposed Muon Collider, FCC and other HEP hadron colliders. This is a Directed R&D where direction is given by the field range and industry involvement for high-automation and industry-ready technology. The plan includes ten milestones, to be achieved in 6-8 years at the cost of 5-7 $M/year.

43 PARTICLE ACCELERATORS↗
DOE OSTI2020

Materials Data on Nb(PO3)4 by Materials Project

Nb(PO3)4 crystallizes in the orthorhombic Pbcn space group. The structure is three-dimensional. Nb4+ is bonded to six O2- atoms to form NbO6 octahedra that share corners with six PO4 tetrahedra. There are four shorter (2.04 Å) and two longer (2.13 Å) Nb–O bond lengths. There are two inequivalent P5+ sites. In the first P5+ site, P5+ is bonded to four O2- atoms to form PO4 tetrahedra that share corners with two equivalent NbO6 octahedra and corners with two equivalent PO4 tetrahedra. The corner-sharing octahedra tilt angles range from 38–43°. There are a spread of P–O bond distances ranging from 1.51–1.58 Å. In the second P5+ site, P5+ is bonded to four O2- atoms to form PO4 tetrahedra that share a cornercorner with one NbO6 octahedra and corners with two equivalent PO4 tetrahedra. The corner-sharing octahedral tilt angles are 36°. There are a spread of P–O bond distances ranging from 1.46–1.65 Å. There are six inequivalent O2- sites. In the first O2- site, O2- is bonded in a bent 150 degrees geometry to one Nb4+ and one P5+ atom. In the second O2- site, O2- is bonded in a distorted bent 150 degrees geometry to two P5+ atoms. In the third O2- site, O2- is bonded in a distorted bent 150 degrees geometry to one Nb4+ and one P5+ atom. In the fourth O2- site, O2- is bonded in a distorted bent 120 degrees geometry to two P5+ atoms. In the fifth O2- site, O2- is bonded in a single-bond geometry to one P5+ atom. In the sixth O2- site, O2- is bonded in a bent 150 degrees geometry to one Nb4+ and one P5+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Nb(SeCl)2 by Materials Project

NbSe2Cl2 crystallizes in the triclinic P-1 space group. The structure is two-dimensional and consists of one NbSe2Cl2 sheet oriented in the (0, 0, 1) direction. Nb5+ is bonded in a 8-coordinate geometry to four Se+1.50- and four Cl1- atoms. There are two shorter (2.64 Å) and two longer (2.66 Å) Nb–Se bond lengths. There are a spread of Nb–Cl bond distances ranging from 2.61–2.65 Å. There are two inequivalent Se+1.50- sites. In the first Se+1.50- site, Se+1.50- is bonded in a 9-coordinate geometry to two equivalent Nb5+ atoms. In the second Se+1.50- site, Se+1.50- is bonded in a 10-coordinate geometry to two equivalent Nb5+ atoms. There are two inequivalent Cl1- sites. In the first Cl1- site, Cl1- is bonded in a distorted water-like geometry to two equivalent Nb5+ atoms. In the second Cl1- site, Cl1- is bonded in a distorted water-like geometry to two equivalent Nb5+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Nb(SCl)2 by Materials Project

NbS2Cl2 crystallizes in the monoclinic C2/m space group. The structure is two-dimensional and consists of one NbS2Cl2 sheet oriented in the (0, 0, 1) direction. Nb5+ is bonded in a 8-coordinate geometry to four S+1.50- and four equivalent Cl1- atoms. There are two shorter (2.50 Å) and two longer (2.51 Å) Nb–S bond lengths. There are two shorter (2.59 Å) and two longer (2.64 Å) Nb–Cl bond lengths. There are two inequivalent S+1.50- sites. In the first S+1.50- site, S+1.50- is bonded in a 5-coordinate geometry to two equivalent Nb5+ atoms. In the second S+1.50- site, S+1.50- is bonded in a 10-coordinate geometry to two equivalent Nb5+ atoms. Cl1- is bonded in a distorted water-like geometry to two equivalent Nb5+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Nb(NiP4)4 by Materials Project

Nb(NiP4)4 crystallizes in the monoclinic C2/c space group. The structure is three-dimensional. Nb2+ is bonded in a 8-coordinate geometry to eight P+0.50- atoms. There are a spread of Nb–P bond distances ranging from 2.53–2.59 Å. There are two inequivalent Ni+1.50+ sites. In the first Ni+1.50+ site, Ni+1.50+ is bonded to six P+0.50- atoms to form NiP6 octahedra that share corners with six NiP6 octahedra, corners with ten PNbNiP2 tetrahedra, and an edgeedge with one NiP6 octahedra. The corner-sharing octahedra tilt angles range from 57–65°. There are a spread of Ni–P bond distances ranging from 2.23–2.39 Å. In the second Ni+1.50+ site, Ni+1.50+ is bonded to six P+0.50- atoms to form NiP6 octahedra that share corners with four equivalent NiP6 octahedra and corners with nine PNbNiP2 tetrahedra. The corner-sharing octahedra tilt angles range from 57–64°. There are a spread of Ni–P bond distances ranging from 2.27–2.33 Å. There are eight inequivalent P+0.50- sites. In the first P+0.50- site, P+0.50- is bonded to one Nb2+, one Ni+1.50+, and two P+0.50- atoms to form distorted PNbNiP2 tetrahedra that share corners with three NiP6 octahedra, corners with nine PNbNiP2 tetrahedra, and an edgeedge with one PNbNiP2 tetrahedra. The corner-sharing octahedra tilt angles range from 67–74°. There are one shorter (2.24 Å) and one longer (2.25 Å) P–P bond lengths. In the second P+0.50- site, P+0.50- is bonded to two Ni+1.50+ and two P+0.50- atoms to form distorted PNi2P2 tetrahedra that share a cornercorner with one NiP6 octahedra and corners with eleven PNbNiP2 tetrahedra. The corner-sharing octahedral tilt angles are 71°. The P–P bond length is 2.25 Å. In the third P+0.50- site, P+0.50- is bonded to three Ni+1.50+ and one P+0.50- atom to form distorted PNi3P tetrahedra that share corners with two equivalent NiP6 octahedra, corners with thirteen PNbNiP2 tetrahedra, and an edgeedge with one PNi3P tetrahedra. The corner-sharing octahedra tilt angles range from 73–76°. The P–P bond length is 2.21 Å. In the fourth P+0.50- site, P+0.50- is bonded to two equivalent Ni+1.50+ and two P+0.50- atoms to form distorted PNi2P2 tetrahedra that share corners with three NiP6 octahedra and corners with twelve PNi2P2 tetrahedra. The corner-sharing octahedra tilt angles range from 70–83°. The P–P bond length is 2.25 Å. In the fifth P+0.50- site, P+0.50- is bonded in a 4-coordinate geometry to one Nb2+, one Ni+1.50+, and two P+0.50- atoms. The P–P bond length is 2.25 Å. In the sixth P+0.50- site, P+0.50- is bonded to one Nb2+ and three P+0.50- atoms to form distorted PNbP3 tetrahedra that share corners with six NiP6 octahedra and corners with eight PNbNiP2 tetrahedra. The corner-sharing octahedra tilt angles range from 58–76°. The P–P bond length is 2.25 Å. In the seventh P+0.50- site, P+0.50- is bonded to two Ni+1.50+ and two P+0.50- atoms to form distorted PNi2P2 tetrahedra that share a cornercorner with one NiP6 octahedra and corners with eleven PNbNiP2 tetrahedra. The corner-sharing octahedral tilt angles are 71°. The P–P bond length is 2.24 Å. In the eighth P+0.50- site, P+0.50- is bonded to one Nb2+, one Ni+1.50+, and two P+0.50- atoms to form distorted PNbNiP2 tetrahedra that share corners with three NiP6 octahedra, corners with nine PNbNiP2 tetrahedra, and an edgeedge with one PNbNiP2 tetrahedra. The corner-sharing octahedra tilt angles range from 66–75°.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Nb(SeBr)2 by Materials Project

NbSe2Br2 crystallizes in the triclinic P-1 space group. The structure is two-dimensional and consists of one NbSe2Br2 sheet oriented in the (0, 0, 1) direction. Nb5+ is bonded in a 8-coordinate geometry to four Se+1.50- and four Br1- atoms. There are two shorter (2.63 Å) and two longer (2.66 Å) Nb–Se bond lengths. There are a spread of Nb–Br bond distances ranging from 2.78–2.82 Å. There are two inequivalent Se+1.50- sites. In the first Se+1.50- site, Se+1.50- is bonded in a 10-coordinate geometry to two equivalent Nb5+ atoms. In the second Se+1.50- site, Se+1.50- is bonded in a 2-coordinate geometry to two equivalent Nb5+ atoms. There are two inequivalent Br1- sites. In the first Br1- site, Br1- is bonded in a distorted water-like geometry to two equivalent Nb5+ atoms. In the second Br1- site, Br1- is bonded in a distorted water-like geometry to two equivalent Nb5+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Nb(SeBr)2 by Materials Project

NbSe2Br2 crystallizes in the monoclinic C2/m space group. The structure is two-dimensional and consists of one NbSe2Br2 sheet oriented in the (0, 0, 1) direction. Nb5+ is bonded in a 8-coordinate geometry to four Se+1.50- and four equivalent Br1- atoms. There are two shorter (2.63 Å) and two longer (2.66 Å) Nb–Se bond lengths. There are two shorter (2.78 Å) and two longer (2.81 Å) Nb–Br bond lengths. There are two inequivalent Se+1.50- sites. In the first Se+1.50- site, Se+1.50- is bonded in a 5-coordinate geometry to two equivalent Nb5+ atoms. In the second Se+1.50- site, Se+1.50- is bonded in a 10-coordinate geometry to two equivalent Nb5+ atoms. Br1- is bonded in a distorted water-like geometry to two equivalent Nb5+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Nb(PO3)4 by Materials Project

Nb(PO3)4 crystallizes in the monoclinic C2/c space group. The structure is three-dimensional. Nb4+ is bonded to six O2- atoms to form NbO6 octahedra that share corners with six PO4 tetrahedra. There are two shorter (2.02 Å) and four longer (2.11 Å) Nb–O bond lengths. There are two inequivalent P5+ sites. In the first P5+ site, P5+ is bonded to four O2- atoms to form PO4 tetrahedra that share corners with two equivalent NbO6 octahedra and corners with two equivalent PO4 tetrahedra. The corner-sharing octahedra tilt angles range from 26–49°. There are a spread of P–O bond distances ranging from 1.50–1.60 Å. In the second P5+ site, P5+ is bonded to four O2- atoms to form PO4 tetrahedra that share a cornercorner with one NbO6 octahedra and corners with two equivalent PO4 tetrahedra. The corner-sharing octahedral tilt angles are 44°. There are a spread of P–O bond distances ranging from 1.45–1.65 Å. There are six inequivalent O2- sites. In the first O2- site, O2- is bonded in a bent 150 degrees geometry to one Nb4+ and one P5+ atom. In the second O2- site, O2- is bonded in a distorted bent 150 degrees geometry to one Nb4+ and one P5+ atom. In the third O2- site, O2- is bonded in a bent 120 degrees geometry to two P5+ atoms. In the fourth O2- site, O2- is bonded in a bent 150 degrees geometry to two P5+ atoms. In the fifth O2- site, O2- is bonded in a distorted bent 120 degrees geometry to one Nb4+ and one P5+ atom. In the sixth O2- site, O2- is bonded in a single-bond geometry to one P5+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Nb(SO4)2 by Materials Project

Nb(SO4)2 crystallizes in the orthorhombic Pbca space group. The structure is three-dimensional. Nb4+ is bonded to six O2- atoms to form NbO6 octahedra that share corners with six SO4 tetrahedra. There are a spread of Nb–O bond distances ranging from 2.06–2.12 Å. There are two inequivalent S6+ sites. In the first S6+ site, S6+ is bonded to four O2- atoms to form SO4 tetrahedra that share corners with three equivalent NbO6 octahedra. The corner-sharing octahedra tilt angles range from 39–51°. There are a spread of S–O bond distances ranging from 1.43–1.52 Å. In the second S6+ site, S6+ is bonded to four O2- atoms to form SO4 tetrahedra that share corners with three equivalent NbO6 octahedra. The corner-sharing octahedra tilt angles range from 44–48°. There are a spread of S–O bond distances ranging from 1.43–1.52 Å. There are eight inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted bent 120 degrees geometry to one Nb4+ and one S6+ atom. In the second O2- site, O2- is bonded in a distorted bent 150 degrees geometry to one Nb4+ and one S6+ atom. In the third O2- site, O2- is bonded in a bent 150 degrees geometry to one Nb4+ and one S6+ atom. In the fourth O2- site, O2- is bonded in a single-bond geometry to one S6+ atom. In the fifth O2- site, O2- is bonded in a distorted bent 150 degrees geometry to one Nb4+ and one S6+ atom. In the sixth O2- site, O2- is bonded in a single-bond geometry to one S6+ atom. In the seventh O2- site, O2- is bonded in a bent 120 degrees geometry to one Nb4+ and one S6+ atom. In the eighth O2- site, O2- is bonded in a bent 150 degrees geometry to one Nb4+ and one S6+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Nb(Mo3S4)2 by Materials Project

Nb(Mo3S4)2 crystallizes in the trigonal R-3 space group. The structure is three-dimensional. Nb2+ is bonded in a body-centered cubic geometry to eight S2- atoms. There are two shorter (2.54 Å) and six longer (2.86 Å) Nb–S bond lengths. Mo+2.33+ is bonded to five S2- atoms to form a mixture of corner and edge-sharing MoS5 trigonal bipyramids. There are a spread of Mo–S bond distances ranging from 2.42–2.58 Å. There are two inequivalent S2- sites. In the first S2- site, S2- is bonded in a 1-coordinate geometry to one Nb2+ and three equivalent Mo+2.33+ atoms. In the second S2- site, S2- is bonded in a 5-coordinate geometry to one Nb2+ and four equivalent Mo+2.33+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Nb(H2Se)2 by Materials Project

(NbH3Se2)2H2 crystallizes in the monoclinic C2/m space group. The structure is two-dimensional and consists of four hydrogen molecules and two NbH3Se2 sheets oriented in the (0, 0, 1) direction. In each NbH3Se2 sheet, Nb2+ is bonded in a 6-coordinate geometry to three H+0.50+ and three equivalent Se2- atoms. There is two shorter (1.88 Å) and one longer (1.90 Å) Nb–H bond length. There are one shorter (2.81 Å) and two longer (2.83 Å) Nb–Se bond lengths. There are two inequivalent H+0.50+ sites. In the first H+0.50+ site, H+0.50+ is bonded in a T-shaped geometry to one Nb2+ and two equivalent Se2- atoms. There is one shorter (1.95 Å) and one longer (1.98 Å) H–Se bond length. In the second H+0.50+ site, H+0.50+ is bonded in a T-shaped geometry to one Nb2+ and two equivalent Se2- atoms. Both H–Se bond lengths are 1.94 Å. There are two inequivalent Se2- sites. In the first Se2- site, Se2- is bonded in a hexagonal planar geometry to six H+0.50+ atoms. In the second Se2- site, Se2- is bonded in a distorted T-shaped geometry to three equivalent Nb2+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Nb(BMo)2 by Materials Project

Nb(MoB)2 crystallizes in the tetragonal P4/mbm space group. The structure is three-dimensional. Nb2+ is bonded in a square co-planar geometry to four equivalent B3- atoms. All Nb–B bond lengths are 2.49 Å. Mo2+ is bonded in a distorted hexagonal planar geometry to six equivalent B3- atoms. There are four shorter (2.39 Å) and two longer (2.47 Å) Mo–B bond lengths. B3- is bonded in a 9-coordinate geometry to two equivalent Nb2+, six equivalent Mo2+, and one B3- atom. The B–B bond length is 1.89 Å.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Nb(Cu3O4)2 by Materials Project

Nb(Cu3O4)2 crystallizes in the cubic Fm-3m space group. The structure is three-dimensional. Nb5+ is bonded in a body-centered cubic geometry to eight equivalent O2- atoms. All Nb–O bond lengths are 2.18 Å. Cu+1.83+ is bonded in a square co-planar geometry to four equivalent O2- atoms. All Cu–O bond lengths are 1.96 Å. O2- is bonded to one Nb5+ and three equivalent Cu+1.83+ atoms to form a mixture of corner and edge-sharing ONbCu3 tetrahedra.

36 MATERIALS SCIENCE↗
DOE OSTI2024

Comparison of the Effect of 2 at. % Additions of Nb and Ta on the 1100 °C Oxidation Behavior of Ni-6Al-(4,6,8) Cr Model Alloys

To continue improving alloy performance in harsh service environments, the development of alumina-forming nickel-based superalloys is essential. Current generations of these alloys heavily rely on the addition of refractory elements to enhance their mechanical properties at high temperatures; however, a systematic understanding of how such additions affect the overall oxidation behavior is still not well established, particularly from the standpoint of predicting the transition from internal to external alumina formation. The present work seeks to better understand the intrinsic effects that common minor additions of Ta and Nb have on the oxidation behavior of alumina-scale-forming γ-Ni model alloys. By combining a novel simulation approach with high-temperature oxidation experiments and advanced characterization techniques, the present study provides insightful details on the differing effects that 2 at. % addition of Ta and Nb have on the alumina scale formation of Ni-based alloys during 1100 °C oxidation.

Rodriguez, Rafael↗
DOE OSTI2021

Measurement of light-by-light scattering and search for axion-like particles with 2.2 nb -1 of Pb+Pb data with the ATLAS detector

This paper describes a measurement of light-by-light scattering based on Pb+Pb collision data recorded by the ATLAS experiment during Run 2 of the LHC. The study uses 2.2 nb -1 of integrated luminosity collected in 2015 and 2018 at s N N = 5.02. Light-by-light scattering candidates are selected in events with two photons produced exclusively, each with transverse energy E T &#x03B3;<!-- γ --> > 2.5 GeV, pseudorapidity |η γ | < 2.37, diphoton invariant mass m γγ > 5 GeV, and with small diphoton transverse momentum and diphoton acoplanarity. The integrated and differential fiducial cross sections are measured and compared with theoretical predictions. The diphoton invariant mass distribution is used to set limits on the production of axion-like particles. This result provides the most stringent limits to date on axion-like particle production for masses in the range 6–100 GeV. Cross sections above 2 to 70 nb are excluded at the 95% CL in that mass interval.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2022

Determination of the structure of lithium niobosilicate glasses by molecular dynamics simulation with a new Nb-O potential

A partial charge empirical potential for the Nb-O pair has been developed based on existing parameters of other pairs in a Teter potential to enable molecular dynamics simulations of both lithium niobate crystal and lithium niobosilicate glasses. The developed potential is capable of describing structural features of lithium niobosilicate glasses in a wide composition range, including niobium coordination number and bond length, density, bond angle distribution, polyhedral distribution and fraction of bridging oxygen. Furthermore, the results obtained using this new potential show good agreement with experimental data of density and structure from Raman spectroscopy of lithium niobosilicate glasses and X-ray absorption spectroscopy near Nb K-edge.

36 MATERIALS SCIENCE↗
DOE OSTI2024

Residual resistance ratio measurement system for Nb 3 Sn wires extracted from Rutherford cables

Residual resistance ratio (RRR) of superconducting strands is an important parameter for magnet electrical stability. RRR serves as a measure of the low-temperature electrical conductivity of the copper within a conductor that has a copper stabilization matrix. For Nb 3 Sn, due to the need of a reaction heat treatment, the technical requirements for high quality measurements of strands extracted from Rutherford cables are particularly demanding. Quality of wire, cabling deformation, heat treatment temperature, heat treatment atmosphere, sample handling, and measurement methods can all affect the RRR. Therefore, as an integral part of the electrical quality control (QC) of Nb 3 Sn Rutherford cables manufactured at the Lawrence Berkeley National Laboratory, it was prudent that we established a RRR measurement system that can isolate the assessment of cable-fabrication-related impacts from sample preparation and measurement factors. Here we describe a bespoke cryocooler-based measurement system, capable of measuring RRR of over 80 samples in a single cooldown. The samples are mounted on custom-designed printed circuit boards that accommodate the shape of strands extracted from a Rutherford cable without added deformation, which we will show is critical in ensuring that the measurements accurately represent the RRR values of the conductor within the cable. Using this sample mounting solution, we routinely measure the overall RRR of the strand as well as individual intra-strand sections corresponding to both cable edges and cable broad faces with high reproducibility. Such measurements provide valuable information on the variation of RRR along the length of the strands as well as across strand productions and cable runs over time.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗