Engineering Papers⌕ Search

SEARCH · Engineering Papers

Results for “Zr”

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.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 235 records · Page 13
All sourcesNASA NTRSDOE OSTI
DOE OSTI2024

Thermal Conductivity Degradation in High Burnup U-Pu-Zr Fuel

Recent advancements in the characterization of irradiated U-Pu-Zr fuels have revealed complexities that challenge existing understanding of constituent redistribution. Traditionally, models have proposed three concentric regions within the fuel, each characterized by distinctive phases and porosity. However, through detailed analysis of high burnup U-Pu-Zr, we discovered the presence of four distinct constituent redistribution regions. Particularly novel is the observation of significant Pu redistribution, a previously unreported phenomenon that necessitates a reevaluation of current models. This work aims to delve deeper into these findings, seeking to correlate mesoscale measurements of thermal diffusivity and respective thermal conductivity with the phases present in each redistribution region. To achieve this objective, we employed mesoscale thermoreflectance methods using the unique, Idaho National Laboratory (INL) developed, Thermal Conductivity Microscope (TCM) at INL’s Irradiated Materials Characterization Laboratory. The TCM employs two tightly focused lasers: one for heating to generate periodic thermal waves in the substrate, and another spatially separated probe laser to detect changes in the optical reflectivity of the gold-coated substrate resulting from thermal wave diffusion. We conducted several thermal diffusivity measurements within each region of constituent redistribution of a U-19Pu-10Zr fuel pin cross section irradiated to 11 at. % burnup. The TCM measurement positions strategically aligned with transmission electron microscopy (TEM) lift-out locations previously collected from the fuel sample. Complementary microstructural analysis techniques such as optical and scanning electron microscopy (OM/SEM), electron probe microanalysis for chemical compositions, and TEM-based selective area electron diffraction (SAED) analysis for crystallographic insights into each phase were also utilized. This comprehensive approach allowed us to correlate local thermal diffusivity data with microstructural characteristics, enabling the computation of local thermal conductivity at each position. The significance of this contribution lies in its pioneering use of the TCM for ternary fuel mesoscale examination, shedding light on the previously overlooked effects of Pu redistribution on local thermal conductivity. By informing current models capturing constituent redistribution and heat transfer, our findings pave the way for more accurate predictions of metallic fuel performance. Moreover, this work sets the stage for future comparisons with similar TCM examinations on U-19Pu-10Zr fuels at ultra-low burnup, facilitating a comprehensive understanding of thermal property changes across different burnup levels. Ultimately, our study not only enriches our understanding of the thermophysical properties of individual redistribution regions within U-Pu-Zr fuel but also offers valuable insights for the design and operational parameters of proposed next-generation fast reactors.

11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗
DOE OSTI2020

Materials Data on Zr(NiP)2 by Materials Project

Zr(NiP)2 crystallizes in the tetragonal I4/mmm space group. The structure is three-dimensional. Zr2+ is bonded in a distorted body-centered cubic geometry to eight equivalent P3- atoms. All Zr–P bond lengths are 2.85 Å. Ni2+ is bonded to four equivalent P3- atoms to form a mixture of edge and corner-sharing NiP4 tetrahedra. All Ni–P bond lengths are 2.24 Å. P3- is bonded in a 9-coordinate geometry to four equivalent Zr2+, four equivalent Ni2+, and one P3- atom. The P–P bond length is 2.25 Å.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Zr(SO4)2 by Materials Project

Zr(SO4)2 crystallizes in the orthorhombic Pnma space group. The structure is three-dimensional. Zr4+ is bonded to seven O2- atoms to form distorted ZrO7 pentagonal bipyramids that share corners with seven SO4 tetrahedra. There are a spread of Zr–O bond distances ranging from 2.09–2.30 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 ZrO7 pentagonal bipyramids. There are a spread of S–O bond distances ranging from 1.43–1.50 Å. In the second S6+ site, S6+ is bonded to four O2- atoms to form SO4 tetrahedra that share corners with four equivalent ZrO7 pentagonal bipyramids. There is three shorter (1.48 Å) and one longer (1.49 Å) S–O bond length. There are six inequivalent O2- sites. In the first O2- site, O2- is bonded in a 1-coordinate geometry to one Zr4+ and one S6+ atom. In the second O2- site, O2- is bonded in a bent 150 degrees geometry to one Zr4+ and one S6+ atom. In the third O2- site, O2- is bonded in a distorted bent 150 degrees geometry to one Zr4+ 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 linear geometry to one Zr4+ and one S6+ atom. In the sixth O2- site, O2- is bonded in a distorted bent 150 degrees geometry to one Zr4+ and one S6+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Zr(FeSi)2 by Materials Project

Zr(FeSi)2 crystallizes in the tetragonal I4/mmm space group. The structure is three-dimensional. Zr2+ is bonded in a distorted body-centered cubic geometry to eight equivalent Si4- atoms. All Zr–Si bond lengths are 2.98 Å. Fe3+ is bonded to four equivalent Si4- atoms to form a mixture of corner and edge-sharing FeSi4 tetrahedra. All Fe–Si bond lengths are 2.24 Å. Si4- is bonded in a 9-coordinate geometry to four equivalent Zr2+, four equivalent Fe3+, and one Si4- atom. The Si–Si bond length is 2.40 Å.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Zr(SeCl6)2 by Materials Project

Zr(SeCl6)2 crystallizes in the orthorhombic Fdd2 space group. The structure is three-dimensional. Zr4+ is bonded to six Cl1- atoms to form ZrCl6 octahedra that share corners with two equivalent SeCl6 octahedra and edges with two equivalent SeCl6 octahedra. The corner-sharing octahedral tilt angles are 46°. There are a spread of Zr–Cl bond distances ranging from 2.47–2.52 Å. Se4+ is bonded to six Cl1- atoms to form distorted SeCl6 octahedra that share a cornercorner with one ZrCl6 octahedra and an edgeedge with one ZrCl6 octahedra. The corner-sharing octahedral tilt angles are 46°. There are a spread of Se–Cl bond distances ranging from 2.19–2.96 Å. There are six inequivalent Cl1- sites. In the first Cl1- site, Cl1- is bonded in a distorted single-bond geometry to one Zr4+ and one Se4+ atom. In the second Cl1- site, Cl1- is bonded in a single-bond geometry to one Se4+ atom. In the third Cl1- site, Cl1- is bonded in a single-bond geometry to one Se4+ atom. In the fourth Cl1- site, Cl1- is bonded in a distorted water-like geometry to one Zr4+ and one Se4+ atom. In the fifth Cl1- site, Cl1- is bonded in a distorted water-like geometry to one Zr4+ and one Se4+ atom. In the sixth Cl1- site, Cl1- is bonded in a single-bond geometry to one Se4+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Zr(MoO4)2 by Materials Project

ZrMo2O8 crystallizes in the trigonal P-31c space group. The structure is two-dimensional and consists of two ZrMo2O8 sheets oriented in the (0, 0, 1) direction. there are two inequivalent Zr4+ sites. In the first Zr4+ site, Zr4+ is bonded to six O2- atoms to form ZrO6 octahedra that share corners with six equivalent MoO4 tetrahedra. All Zr–O bond lengths are 2.11 Å. In the second Zr4+ site, Zr4+ is bonded to six equivalent O2- atoms to form ZrO6 octahedra that share corners with six equivalent MoO4 tetrahedra. All Zr–O bond lengths are 2.11 Å. Mo6+ is bonded to four O2- atoms to form MoO4 tetrahedra that share corners with three ZrO6 octahedra. The corner-sharing octahedra tilt angles range from 11–21°. There is one shorter (1.73 Å) and three longer (1.82 Å) Mo–O bond length. There are four inequivalent O2- sites. In the first O2- site, O2- is bonded in a single-bond geometry to one Mo6+ atom. In the second O2- site, O2- is bonded in a linear geometry to one Zr4+ and one Mo6+ atom. In the third O2- site, O2- is bonded in a bent 150 degrees geometry to one Zr4+ and one Mo6+ atom. In the fourth O2- site, O2- is bonded in a linear geometry to one Zr4+ and one Mo6+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Zr(SiNi)2 by Materials Project

Zr(NiSi)2 crystallizes in the tetragonal I4/mmm space group. The structure is three-dimensional. Zr4+ is bonded in a distorted body-centered cubic geometry to eight equivalent Si4- atoms. All Zr–Si bond lengths are 2.90 Å. Ni2+ is bonded to four equivalent Si4- atoms to form a mixture of edge and corner-sharing NiSi4 tetrahedra. All Ni–Si bond lengths are 2.27 Å. Si4- is bonded in a 9-coordinate geometry to four equivalent Zr4+, four equivalent Ni2+, and one Si4- atom. The Si–Si bond length is 2.33 Å.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Zr(CuP)2 by Materials Project

Zr(CuP)2 crystallizes in the trigonal P-3m1 space group. The structure is three-dimensional. Zr4+ is bonded to six equivalent P3- atoms to form ZrP6 octahedra that share corners with twelve equivalent CuP4 tetrahedra, edges with six equivalent ZrP6 octahedra, and edges with six equivalent CuP4 tetrahedra. All Zr–P bond lengths are 2.70 Å. Cu1+ is bonded to four equivalent P3- atoms to form CuP4 tetrahedra that share corners with six equivalent ZrP6 octahedra, corners with six equivalent CuP4 tetrahedra, edges with three equivalent ZrP6 octahedra, and edges with three equivalent CuP4 tetrahedra. The corner-sharing octahedra tilt angles range from 18–55°. There are three shorter (2.30 Å) and one longer (2.40 Å) Cu–P bond lengths. P3- is bonded to three equivalent Zr4+ and four equivalent Cu1+ atoms to form a mixture of distorted edge and corner-sharing PZr3Cu4 pentagonal bipyramids.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Zr(Ni2As)2 by Materials Project

Zr(Ni2As)2 crystallizes in the tetragonal P4_2/mnm space group. The structure is three-dimensional. Zr2+ is bonded to six equivalent As3- atoms to form a mixture of edge and corner-sharing ZrAs6 octahedra. The corner-sharing octahedral tilt angles are 41°. There are two shorter (2.84 Å) and four longer (2.87 Å) Zr–As bond lengths. Ni1+ is bonded in a trigonal non-coplanar geometry to three equivalent As3- atoms. All Ni–As bond lengths are 2.36 Å. As3- is bonded in a 9-coordinate geometry to three equivalent Zr2+ and six equivalent Ni1+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Zr(NF3)2 by Materials Project

ZrF4(NF)2 crystallizes in the orthorhombic Pca2_1 space group. The structure is one-dimensional and consists of sixteen monofluoroamine molecules and four ZrF4 ribbons oriented in the (1, 0, 0) direction. In each ZrF4 ribbon, there are two inequivalent Zr4+ sites. In the first Zr4+ site, Zr4+ is bonded to six F1- atoms to form a mixture of distorted corner and face-sharing ZrF6 octahedra. The corner-sharing octahedral tilt angles are 34°. There are a spread of Zr–F bond distances ranging from 1.92–2.20 Å. In the second Zr4+ site, Zr4+ is bonded to six F1- atoms to form a mixture of distorted corner and face-sharing ZrF6 octahedra. The corner-sharing octahedral tilt angles are 34°. There are a spread of Zr–F bond distances ranging from 1.92–2.24 Å. There are eight inequivalent F1- sites. In the first F1- site, F1- is bonded in a single-bond geometry to one Zr4+ atom. In the second F1- site, F1- is bonded in a single-bond geometry to one Zr4+ atom. In the third F1- site, F1- is bonded in a single-bond geometry to one Zr4+ atom. In the fourth F1- site, F1- is bonded in an L-shaped geometry to two Zr4+ atoms. In the fifth F1- site, F1- is bonded in an L-shaped geometry to two Zr4+ atoms. In the sixth F1- site, F1- is bonded in an L-shaped geometry to two Zr4+ atoms. In the seventh F1- site, F1- is bonded in a bent 150 degrees geometry to two Zr4+ atoms. In the eighth F1- site, F1- is bonded in a single-bond geometry to one Zr4+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Zr(SiPd)3 by Materials Project

Zr(PdSi)3 crystallizes in the orthorhombic Cmcm space group. The structure is three-dimensional. Zr4+ is bonded to eight equivalent Si4- atoms to form distorted ZrSi8 hexagonal bipyramids that share corners with four equivalent PdSi4 tetrahedra, edges with four equivalent ZrSi8 hexagonal bipyramids, edges with two equivalent PdSi4 tetrahedra, and faces with four equivalent ZrSi8 hexagonal bipyramids. There are four shorter (2.81 Å) and four longer (2.95 Å) Zr–Si bond lengths. There are two inequivalent Pd+2.67+ sites. In the first Pd+2.67+ site, Pd+2.67+ is bonded to four Si4- atoms to form PdSi4 tetrahedra that share corners with four equivalent ZrSi8 hexagonal bipyramids, corners with two equivalent PdSi4 tetrahedra, and edges with two equivalent ZrSi8 hexagonal bipyramids. There are two shorter (2.43 Å) and two longer (2.50 Å) Pd–Si bond lengths. In the second Pd+2.67+ site, Pd+2.67+ is bonded in a 5-coordinate geometry to five Si4- atoms. There are a spread of Pd–Si bond distances ranging from 2.51–2.58 Å. There are two inequivalent Si4- sites. In the first Si4- site, Si4- is bonded in a 8-coordinate geometry to four equivalent Zr4+, three Pd+2.67+, and one Si4- atom. The Si–Si bond length is 2.36 Å. In the second Si4- site, Si4- is bonded in a 8-coordinate geometry to eight Pd+2.67+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2022

An experimentally validated mesoscale model for the effective thermal conductivity of U-Zr fuels

An experimentally validated mesoscale model was developed to simulate the effective thermal conductivity (ETC) of metallic U and U–Zr nuclear fuels. The effects of microstructure, temperature, composition, and interfacial thermal resistance (ITR) were investigated. Companion experiments were conducted to validate the model. The numerical simulations clearly demonstrate that accounting for the interface (Kapitza) thermal resistance and Zr precipitation is necessary to improve the model predictions. The dependence of the effective Kapitza resistance of depleted-U and U-10Zr on temperature was determined. Finally, for both materials, the largest difference between the model calculations and the experimental data was about 4.5%, which is within the precision of the experimental measurements.

11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗
DOE OSTI2024

Breaking Barriers in Chalcogenide Perovskite Synthesis: A Generalized Framework for Fabrication of BaMS 3 (M═Ti, Zr, Hf) Materials

Abstract Chalcogenide perovskites have garnered increasing attention as stable, non‐toxic alternatives to lead halide perovskites. However, their conventional synthesis at high temperatures (>1000 °C) has hindered widespread adoption. Recent studies have developed low‐to‐moderate temperature synthesis methods (<600 °C) using reactive precursors, yet a comprehensive understanding of the pivotal factors affecting reproducibility and repeatability remains elusive. This study delineates the critical factors in the low‐temperature synthesis of BaMS 3 (M═Zr, Hf, Ti) compounds and presents a generalized framework. Innovative approaches are developed for synthesizing BaMS 3 compounds using this framework involving organometallics for solution deposition. The molecular precursor routes, employing metal acetylacetonates to generate soluble metal–sulfur bonded complexes and metal–organic compounds to produce soluble metal‐thiolate, metal‐isothiocyanate, and metal‐trithiocarbonate species, are demonstrated to yield carbon‐free BaMS 3 . These methods have achieved the most contiguous films of BaZrS 3 and BaHfS 3 using solution deposition to date. Furthermore, a hybrid solution processing method involving stacking sputter‐deposited Zr and solution‐deposited BaS layers is employed to synthesize a contiguous, oxygen‐free BaZrS 3 film. The diffuse reflectance measurements indicate a direct bandgap of ≈ 1.85 eV for the BaZrS 3 films and ≈ 2.1 eV for the BaHfS 3 film under investigation.

25 ENERGY STORAGE↗
DOE OSTI2022

CeO 2 Doping of Hf 0.5 Zr 0.5 O 2 Thin Films for High Endurance Ferroelectric Memories

Ferroelectric switching is demonstrated in CeO 2 -doped Hf 0.5 Zr 0.5 O 2 (HZCO) thin films with application in back-end-of-line compatible embedded memories. At low cerium oxide doping concentrations (2.0–5.6 mol%), the ferroelectric orthorhombic phase is stabilized after annealing at temperatures below 400 °C. HZCO ferroelectrics show reliable switching characteristics beyond 10 11 cycles in TiN/HZCO/TiN capacitors, several orders of magnitude greater than identically processed Hf 0.5 Zr 0.5 O 2 (HZO) capacitors, without sacrificing polarization and retention. Internal photoemission and photoconductivity experiments show that CeO 2 -doping introduces in-gap states in HZCO that are nearly aligned with TiN Fermi level, facilitating electron injection through these states. Furthermore, the enhanced average bulk conduction, which may lead to more uniform thermal dissipation in the HZCO films, delays irreversible degradation via breakdown that leads to device failure after repeated programming cycles.

36 MATERIALS SCIENCE↗
DOE OSTI2024

Phase Transformation Driven by Oxygen Vacancy Redistribution as the Mechanism of Ferroelectric Hf 0.5 Zr 0.5 O 2 Fatigue

As a promising candidate for nonvolatile memory devices, the hafnia-based ferroelectric system has recently been a hot research topic. Although significant progress has been made over the past decade, the endurance problem is still an obstacle to its final application. In perovskite-based ferroelectrics, such as the well-studied Pb[Zr x Ti 1-x ]O 3 (PZT) family, polarization fatigue has been discussed within the framework of the interaction of charged defects (such as oxygen vacancies) with the moving domains during the switching process, particularly at the electrode-ferroelectric interface. Armed with this background, a hypothesis is set out to test that a similar mechanism can be in play with the hafnia-based ferroelectrics. The conducting perovskite La-Sr-Mn-O is used as the contact electrode to create La 0.67 Sr 0.33 MnO 3 / Hf 0.5 Zr 0.5 O 2 (HZO)/ La 0.67 Sr 0.33 MnO 3 capacitor structures deposited on SrTiO 3 -Si substrates. Nanoscale X-ray diffraction is performed on single capacitors, and a structural phase transition from polar o-phase toward non-polar m-phase is demonstrated during the bipolar switching process. The energy landscape of multiphase HZO has been calculated at varying oxygen vacancy concentrations. Based on both theoretical and experimental results, it is found that a polar to non-polar phase transformation caused by oxygen vacancy redistribution during electric cycling is a likely explanation for fatigue in HZO.

36 MATERIALS SCIENCE↗
DOE OSTI2023

Linker Vacancy Engineering of a Robust ftw–type Zr–MOF for Hexane Isomers Separation

Discrimination of physically similar molecules by porous solids represents an important yet challenging task in industrially relevant chemical separations. Precisely controlled pore dimension and/or tailored pore surface functionality are crucial to achieve high-efficiency separation. Metal-organic frameworks (MOFs) are promising candidates for these challenging separations in light of their structural diversity as well as highly adjustable pore dimension/functionality. We report here a microporous, ftw-type Zr-based MOF structure, HIAM-410 (HIAM=Hoffmann Institute of Advanced Materials), built on hexanuclear Zr 6 cluster and pyrene-1,3,6,8-tetracarboxylate (ptc 4– ). Its crystallographic structure has been determined using continuous rotation electron diffraction (cRED) technique combined with Rietveld refinement against powder X-ray diffraction data, aided by low-dose high-resolution transmission electron microscopy (HRTEM) imaging. The compound features exceptional framework stability that is comparable to the prototype MOF UiO-66. Interestingly, the linker vacancies in the pristine MOF structure could be partially restored by post-synthetic linker insertion. Its separation capability of hexane isomers is enhanced substantially upon the linker vacancy engineering. As a result, the restored structure exhibits efficient splitting of monobranched and dibranched hexane isomers at both room temperature and industrially relevant temperature.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2021

Gallium‐Doping Effects on Structure, Lithium‐Conduction, and Thermochemical Stability of Li 7‐3 x Ga x La 3 Zr 2 O 12 Garnet‐Type Electrolytes

Abstract One of the most promising electrolytes for all‐solid‐state lithium batteries is Li 7 La 3 Zr 2 O 12 . Previously, their thermodynamic stability, Li‐ion conductivity, and structural features induced by Ga‐doping have not been empirically determined or correlated. Here, their interplay was examined for Li 7−3 x Ga x La 3 Zr 2 O 12 with target x Ga=0, 0.25, 0.50, 0.75, and 1.00 atoms per formula unit (apfu). Formation enthalpies, obtained with calorimetry and found to be exothermic at all compositions, linearly decreased in stability with increased x Ga. At dilute x Ga substitution, the formation enthalpy curve shifted stepwise endothermically, and the conductivity increased to a maximum, coinciding with 0.529 Ga apfu. This correlated with percolation threshold analysis (0.558 Ga apfu). Further substitution (0.787 Ga apfu) produced a large decrease in the stability and conductivity due to a large increase in point defects and blocked Li‐migration pathways. At x Ga=1.140 apfu, a small exothermic shift was related to defect cluster organization extending the Li hopping distance and decreased Li‐ion conductivity.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2020

NASICON Li 1.2 Mg 0.1 Zr 1.9 (PO 4 ) 3 Solid Electrolyte for an All‐Solid‐State Li‐Metal Battery

Abstract A thin solid electrolyte with a high Li + conductivity is used to separate the metallic lithium anode and the cathode in an all‐solid‐state Li‐metal battery. However, most solid Li‐ion electrolytes have a small electrochemical stability window, large interfacial resistance, and cannot block lithium‐dendrite growth when lithium is plated on charging of the cell. Mg 2+ stabilizes a rhombohedral NASICON‐structured solid electrolyte of the formula Li 1.2 Mg 0.1 Zr 1.9 (PO 4 ) 3 (LMZP). This solid electrolyte has Li‐ion conductivity two orders of magnitude higher at 25 °C than that of the triclinic LiZr 2 (PO 4 ) 3 . 7 Li and 6 Li NMR confirm the Li‐ions in two different crystallographic sites of the NASICON framework with 85% of the Li‐ions having a relatively higher mobility than the other 15%. The anode–electrolyte interface is further investigated with symmetric Li/LMZP/Li cell testing, while the cathode–electrolyte interface is explored with an all‐solid‐state Li/LMZP/LiFePO 4 cell. The enhanced performance of these cells enabled by the Li 1.2 Mg 0.1 Zr 1.9 (PO 4 ) 3 solid electrolyte is stable upon repeated charge/discharge cycling.

Zhou, Qiongyu↗