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At least 397 records · Page 22
All sourcesNASA NTRSDOE OSTI
DOE OSTI2020

Materials Data on Si2NiPd by Materials Project

PdNiSi2 is Modderite-derived structured and crystallizes in the orthorhombic Pmc2_1 space group. The structure is three-dimensional. Pd4+ is bonded to six Si4- atoms to form distorted PdSi6 pentagonal pyramids that share corners with eight equivalent NiSi6 octahedra, corners with four equivalent PdSi6 pentagonal pyramids, edges with four equivalent NiSi6 octahedra, edges with two equivalent PdSi6 pentagonal pyramids, and faces with two equivalent PdSi6 pentagonal pyramids. The corner-sharing octahedra tilt angles range from 46–62°. There are a spread of Pd–Si bond distances ranging from 2.42–2.64 Å. Ni4+ is bonded to six Si4- atoms to form distorted NiSi6 octahedra that share corners with four equivalent NiSi6 octahedra, corners with eight equivalent PdSi6 pentagonal pyramids, edges with two equivalent NiSi6 octahedra, edges with four equivalent PdSi6 pentagonal pyramids, and faces with two equivalent NiSi6 octahedra. The corner-sharing octahedral tilt angles are 47°. There are a spread of Ni–Si bond distances ranging from 2.32–2.48 Å. There are two inequivalent Si4- sites. In the first Si4- site, Si4- is bonded in a 6-coordinate geometry to four equivalent Pd4+, two equivalent Ni4+, and two equivalent Si4- atoms. Both Si–Si bond lengths are 2.73 Å. In the second Si4- site, Si4- is bonded in a 1-coordinate geometry to two equivalent Pd4+, four equivalent Ni4+, and two equivalent Si4- atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Te2PdCl10 by Materials Project

PdTe2Cl10 crystallizes in the monoclinic P2_1/c space group. The structure is zero-dimensional and consists of two PdTe2Cl10 clusters. Pd2+ is bonded in a rectangular see-saw-like geometry to four Cl1- atoms. There are three shorter (2.32 Å) and one longer (2.33 Å) Pd–Cl bond lengths. There are two inequivalent Te4+ sites. In the first Te4+ site, Te4+ is bonded in a 5-coordinate geometry to five Cl1- atoms. There are a spread of Te–Cl bond distances ranging from 2.34–2.86 Å. In the second Te4+ site, Te4+ is bonded in a 6-coordinate geometry to six Cl1- atoms. There are a spread of Te–Cl bond distances ranging from 2.34–3.34 Å. There are ten inequivalent Cl1- sites. In the first Cl1- site, Cl1- is bonded in a distorted water-like geometry to one Pd2+ and one Te4+ atom. In the second Cl1- site, Cl1- is bonded in a 2-coordinate geometry to one Pd2+ and two Te4+ atoms. In the third Cl1- site, Cl1- is bonded in a single-bond geometry to one Te4+ atom. In the fourth Cl1- site, Cl1- is bonded in a single-bond geometry to one Te4+ atom. In the fifth Cl1- site, Cl1- is bonded in a single-bond geometry to one Te4+ atom. In the sixth Cl1- site, Cl1- is bonded in a single-bond geometry to one Te4+ atom. In the seventh Cl1- site, Cl1- is bonded in a single-bond geometry to one Te4+ atom. In the eighth Cl1- site, Cl1- is bonded in a single-bond geometry to one Te4+ atom. In the ninth Cl1- site, Cl1- is bonded in a 2-coordinate geometry to one Pd2+ and one Te4+ atom. In the tenth Cl1- site, Cl1- is bonded in a water-like geometry to one Pd2+ and one Te4+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2024

Programmable Catalyst Structures via Adsorbate-Induced Adatom Assembly

The electronic structure and geometric configuration of oxide-supported metal ions are important coordination properties that can be related to catalytic activity and stability. Herein, we interrogate the coordination environment of mononuclear Pd ions supported on ceria using CO adsorption, infrared vibrational spectroscopy, and DFT modeling. We observed the 15 h continuous co-evolution of a palladium- (2167 cm -1 ) and cerium-carbonyl (2177 cm -1 ) complex by monitoring the $\nu$(CO) infrared region. The slow CO adsorption kinetics were caused by the reactive ligand exchange between an oxygen atom of the support and the CO adsorbate to yield an oxygen vacancy and adsorbed CO 2 . We hypothesize that the co-evolved cerium-carbonyl complex was formed upon CO adsorption at or adjacent to this oxygen vacancy. Our hypothesis was experimentally supported by a dramatic attenuation of the cerium carbonyl signal upon pre-adsorption of water through an apparent competitive adsorption mechanism. The attenuation was also accompanied by a 6 cm -1 redshift of the palladium carbonyl band (2161 cm -1 ) attributed to hydrogen bonding between the carbonyl and a nearby hydroxyl. Characteristic n(CO) stretch frequencies catalogued through CO adsorption onto single crystal ceria by Wöll et al.1 led us to index the cerium carbonyl to the {100} nanofacet of the polycrystalline ceria support. It follows from the observed co-evolution of the two carbonyl complexes that Pd was also adsorbed at the {100} nanofacet. Redeployment of a previously developed DFT model by Ivanova-Shor et al.2 featuring square-planar coordination of Pd2+ at the {100} nanofacet (O 4 Pd) of a Ce 21 O 42 nanoparticle model qualitatively reproduced several experimental observations.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Na2PdS2 by Materials Project

Na2PdS2 crystallizes in the orthorhombic Cmc2_1 space group. The structure is three-dimensional. there are two inequivalent Na1+ sites. In the first Na1+ site, Na1+ is bonded to five S2- atoms to form distorted corner-sharing NaS5 trigonal bipyramids. There are a spread of Na–S bond distances ranging from 2.84–3.00 Å. In the second Na1+ site, Na1+ is bonded in a 6-coordinate geometry to six S2- atoms. There are a spread of Na–S bond distances ranging from 2.96–3.30 Å. Pd2+ is bonded in a square co-planar geometry to four S2- atoms. There are two shorter (2.38 Å) and two longer (2.39 Å) Pd–S bond lengths. There are two inequivalent S2- sites. In the first S2- site, S2- is bonded in a 7-coordinate geometry to five Na1+ and two equivalent Pd2+ atoms. In the second S2- site, S2- is bonded in a 7-coordinate geometry to six Na1+ and two equivalent Pd2+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on K2Pd(CN)4 by Materials Project

K2Pd(CN)4 crystallizes in the monoclinic P2_1/c space group. The structure is three-dimensional. K1+ is bonded in a 6-coordinate geometry to six N3- atoms. There are a spread of K–N bond distances ranging from 2.83–3.34 Å. Pd2+ is bonded in a square co-planar geometry to four C2+ atoms. There is two shorter (1.99 Å) and two longer (2.00 Å) Pd–C bond length. There are two inequivalent C2+ sites. In the first C2+ site, C2+ is bonded in a distorted single-bond geometry to one Pd2+ and one N3- atom. The C–N bond length is 1.18 Å. In the second C2+ site, C2+ is bonded in a distorted single-bond geometry to one Pd2+ and one N3- atom. The C–N bond length is 1.17 Å. There are two inequivalent N3- sites. In the first N3- site, N3- is bonded in a 1-coordinate geometry to three equivalent K1+ and one C2+ atom. In the second N3- site, N3- is bonded in a 1-coordinate geometry to three equivalent K1+ and one C2+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on LaMg2H7Pd by Materials Project

LaMg2PdH7 crystallizes in the orthorhombic P2_12_12_1 space group. The structure is three-dimensional. there are two inequivalent Mg sites. In the first Mg site, Mg is bonded in a 4-coordinate geometry to five H atoms. There are a spread of Mg–H bond distances ranging from 1.93–2.35 Å. In the second Mg site, Mg is bonded in a 6-coordinate geometry to six H atoms. There are a spread of Mg–H bond distances ranging from 1.93–2.28 Å. La is bonded in a 12-coordinate geometry to twelve H atoms. There are a spread of La–H bond distances ranging from 2.33–2.86 Å. Pd is bonded in a distorted tetrahedral geometry to four H atoms. There are a spread of Pd–H bond distances ranging from 1.73–1.76 Å. There are seven inequivalent H sites. In the first H site, H is bonded in a distorted water-like geometry to two Mg and two equivalent La atoms. In the second H site, H is bonded to two Mg and two equivalent La atoms to form distorted corner-sharing HLa2Mg2 tetrahedra. In the third H site, H is bonded in a 1-coordinate geometry to one Mg, two equivalent La, and one Pd atom. In the fourth H site, H is bonded in a distorted rectangular see-saw-like geometry to two Mg, one La, and one Pd atom. In the fifth H site, H is bonded in a 2-coordinate geometry to two equivalent Mg, one La, and one Pd atom. In the sixth H site, H is bonded in a 4-coordinate geometry to one Mg, two equivalent La, and one Pd atom. In the seventh H site, H is bonded in a distorted trigonal planar geometry to one Mg and two equivalent La atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Cs2P4Pd3O14 by Materials Project

Cs2Pd3P4O14 crystallizes in the orthorhombic Cmc2_1 space group. The structure is three-dimensional. there are two inequivalent Cs1+ sites. In the first Cs1+ site, Cs1+ is bonded in a 10-coordinate geometry to ten O2- atoms. There are a spread of Cs–O bond distances ranging from 3.23–3.55 Å. In the second Cs1+ site, Cs1+ is bonded in a 6-coordinate geometry to six O2- atoms. There are a spread of Cs–O bond distances ranging from 3.19–3.46 Å. There are three inequivalent Pd2+ sites. In the first Pd2+ site, Pd2+ is bonded in a square co-planar geometry to four O2- atoms. All Pd–O bond lengths are 2.04 Å. In the second Pd2+ site, Pd2+ is bonded in a rectangular see-saw-like geometry to four O2- atoms. All Pd–O bond lengths are 2.04 Å. In the third Pd2+ site, Pd2+ is bonded in a square co-planar geometry to four O2- atoms. All Pd–O bond lengths are 2.05 Å. There are two inequivalent P5+ sites. In the first P5+ site, P5+ is bonded to four O2- atoms to form corner-sharing PO4 tetrahedra. There are a spread of P–O bond distances ranging from 1.53–1.63 Å. In the second P5+ site, P5+ is bonded to four O2- atoms to form corner-sharing PO4 tetrahedra. There are a spread of P–O bond distances ranging from 1.52–1.64 Å. There are eight inequivalent O2- sites. In the first O2- site, O2- is bonded in a 1-coordinate geometry to two Cs1+, one Pd2+, and one P5+ atom. In the second O2- site, O2- is bonded in a distorted bent 120 degrees geometry to one Cs1+ and two equivalent P5+ atoms. In the third O2- site, O2- is bonded in a 1-coordinate geometry to one Cs1+, one Pd2+, and one P5+ atom. In the fourth O2- site, O2- is bonded in a 2-coordinate geometry to one Cs1+, one Pd2+, and one P5+ atom. In the fifth O2- site, O2- is bonded in a 2-coordinate geometry to one Cs1+, one Pd2+, and one P5+ atom. In the sixth O2- site, O2- is bonded in a distorted bent 120 degrees geometry to one Cs1+, one Pd2+, and one P5+ atom. In the seventh O2- site, O2- is bonded in a bent 120 degrees geometry to one Cs1+ and two equivalent P5+ atoms. In the eighth O2- site, O2- is bonded in a 2-coordinate geometry to one Cs1+, one Pd2+, and one P5+ atom.

36 MATERIALS SCIENCE↗
NASA NTRS1999

Extracellular signal-regulated kinases 1 and 2 activation in endothelial cells exposed to cyclic strain

The aim of this study was to determine whether extracellular signal-regulated kinases 1/2 (ERK1/ERK2) are activated and might play a role in enhanced proliferation and morphological change induced by strain. Bovine aortic endothelial cells (BAEC) were subjected to an average of 6 or 10% strain at a rate of 60 cycles/min for up to 4 h. Cyclic strain caused strain- and time-dependent phosphorylation and activation of ERK1/ERK2. Peak phosphorylation and activation of ERK1/ERK2 induced by 10% strain were at 10 min. A specific ERK1/ERK2 kinase inhibitor, PD-98059, inhibited phosphorylation and activation of ERK1/ERK2 but did not inhibit the increased cell proliferation and cell alignment induced by strain. Treatment of BAEC with 2,5-di-tert-butyl-1, 4-benzohydroquinone, to deplete inositol trisphosphate-sensitive calcium storage, and gadolinium chloride, a Ca2+ channel blocker, did not inhibit the activation of ERK1/ERK2. Strain-induced ERK1/ERK2 activation was partly inhibited by the protein kinase C inhibitor calphostin C and completely inhibited by the tyrosine kinase inhibitor genistein. These data suggest that 1) ERK1/ERK2 are not critically involved in the strain-induced cell proliferation and orientation, 2) strain-dependent activation of ERK1/ERK2 is independent of intracellular and extracellular calcium mobilization, and 3) protein kinase C activation and tyrosine kinase regulate strain-induced activation of ERK1/ERK2.

NASA Discipline Cell Biology↗
DOE OSTI2020

Materials Data on Na2P4Pd3O14 by Materials Project

Na2Pd3P4O14 crystallizes in the tetragonal P4/mnc space group. The structure is three-dimensional. Na1+ is bonded in a 6-coordinate geometry to six O2- atoms. There are a spread of Na–O bond distances ranging from 2.32–2.63 Å. There are two inequivalent Pd2+ sites. In the first Pd2+ site, Pd2+ is bonded in a rectangular see-saw-like geometry to four equivalent O2- atoms. All Pd–O bond lengths are 2.06 Å. In the second Pd2+ site, Pd2+ is bonded in a square co-planar geometry to four O2- atoms. There are two shorter (2.04 Å) and two longer (2.06 Å) Pd–O bond lengths. P5+ is bonded to four O2- atoms to form corner-sharing PO4 tetrahedra. There are a spread of P–O bond distances ranging from 1.53–1.62 Å. There are four inequivalent O2- sites. In the first O2- site, O2- is bonded in a bent 120 degrees geometry to two equivalent P5+ atoms. In the second O2- site, O2- is bonded in a 1-coordinate geometry to one Na1+, one Pd2+, and one P5+ atom. In the third O2- site, O2- is bonded in a distorted trigonal planar geometry to one Na1+, one Pd2+, and one P5+ atom. In the fourth O2- site, O2- is bonded in a 3-coordinate geometry to one Na1+, one Pd2+, and one P5+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2023

A High-Temperature Multipoint Hydrogen Sensor Using an Intrinsic Fabry–Perot Interferometer in Optical Fiber

This paper presents a multiplexable fiber optic chemical sensor with the capability of monitoring hydrogen gas concentration at high temperatures up to 750 °C. The Pd-nanoparticle infused TiO 2 films coated on intrinsic Fabry–Perot interferometer (IFPI) array were used as sensory films. Strains induced upon exposure to hydrogen with varied concentrations can be monitored by IFPI sensors. The fiber sensor shows a repetitive and reversible response when exposed to a low level (1–6%) of hydrogen gas. Uniform sensory behavior across all the sensing cavities is demonstrated and reported in this paper.

47 OTHER INSTRUMENTATION↗
DOE OSTI2020

Materials Data on K3(PdO2)2 by Materials Project

K3Pd2O4 crystallizes in the orthorhombic Cmcm space group. The structure is three-dimensional. there are two inequivalent K sites. In the first K site, K is bonded in a 6-coordinate geometry to six equivalent O atoms. There are a spread of K–O bond distances ranging from 2.83–2.92 Å. In the second K site, K is bonded in a 4-coordinate geometry to four equivalent O atoms. All K–O bond lengths are 2.67 Å. There are two inequivalent Pd sites. In the first Pd site, Pd is bonded in a distorted square co-planar geometry to four equivalent O atoms. All Pd–O bond lengths are 2.04 Å. In the second Pd site, Pd is bonded in a square co-planar geometry to four equivalent O atoms. All Pd–O bond lengths are 2.02 Å. O is bonded to four K and two Pd atoms to form a mixture of distorted corner, edge, and face-sharing OK4Pd2 octahedra. The corner-sharing octahedra tilt angles range from 0–71°.

36 MATERIALS SCIENCE↗
DOE OSTI2025

High-Speed and Hysteresis-Free Near-Infrared Optical Hydrogen Sensor Based on Ti/Pd Bilayer Thin Films

Palladium (Pd) and titanium (Ti) exhibit opposite dielectric responses upon hydrogenation, with stronger effects observed in the near-infrared (NIR) region. Leveraging this contrast, we investigated Ti/Pd bilayer thin films as a platform for NIR hydrogen sensing—particularly at telecommunication-relevant wavelengths, where such devices have remained largely unexplored. Ti/Pd bilayers coated with Teflon AF (TAF) and fabricated via sequential electron-beam and thermal evaporation were characterized using optical transmission measurements under repeated hydrogenation cycles. The Ti (5 nm)/Pd (x = 2.5 nm)/TAF (30 nm) architecture showed a 2.7-fold enhancement in the hydrogen-induced optical contrast at 1550 nm compared to Pd/TAF reference films, attributed to the hydrogen ion exchange between the Ti and Pd layers. The optimized structure, with a Pd thickness of x = 1.9 nm, exhibited hysteresis-free sensing behavior, a rapid response time (t90 < 0.35 s at 4% H2), and a detection limit below 10 ppm. It also demonstrated excellent selectivity with negligible cross-sensitivity to CO2, CH4, and CO, as well as high durability, showing less than 6% signal degradation over 135 hydrogenation cycles. These findings establish a scalable, room-temperature NIR hydrogen sensing platform with strong potential for deployment in automotive, environmental, and industrial applications.

Chemistry↗
DOE OSTI2020

Electrolyte compositions comprising ionic liquids and metal hydride batteries comprising same

Electrolyte compositions comprising a) an ionic liquid and b) a protic acid and/or an organic solvent are suitable for use in electrochemical cells, e.g. metal hydride batteries. The electrolyte compositions may replace the currently employed 30% by weight aqueous KOH. Suitable protic acids include carboxylic acids, mineral acids, sulfonic acids and the like. Suitable organic solvents include organic carbonates, ethers, glymes, ortho esters, polyalkylene glycols, esters, lactones, glycols, formates, sulfones, sulfoxides, amides, alcohols, ketones, nitro solvents, nitrile solvents and combinations thereof. Present batteries may achieve a nominal open-circuit voltage of >1.2 V (volts) and up to about 6 V. The electrolyte compositions allow enlargement of the electrochemical window, thus allowing the use of further cathode active materials. Further cathode active materials include transition metals and their oxides, hydroxides and fluorides; for example, Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Y, Zr, Nb, Mo, Tc, Ru, Rh, Pd, Ag, Cd, Lu, Hf, Ta, W, Re, Os, Ir, Pt and Au and their oxides, hydroxides, oxide/hydroxides and fluorides.

25 ENERGY STORAGE↗
NASA NTRS2002

Reusable Launch Vehicle Attitude Control Using a Time-Varying Sliding Mode Control Technique

In this paper we present a time-varying sliding mode control (TVSMC) technique for reusable launch vehicle (RLV) attitude control in ascent and entry flight phases. In ascent flight the guidance commands Euler roll, pitch and yaw angles, and in entry flight it commands the aerodynamic angles of bank, attack and sideslip. The controller employs a body rate inner loop and the attitude outer loop, which are separated in time-scale by the singular perturbation principle. The novelty of the TVSMC is that both the sliding surface and the boundary layer dynamics can be varied in real time using the PD-eigenvalue assignment technique. This salient feature is used to cope with control command saturation and integrator windup in the presence of severe disturbance or control effector failure, which enhances the robustness and fault tolerance of the controller. The TV-SMC ascent and descent designs are currently being tested with high fidelity, 6-DOF dispersion simulations. The test results will be presented in the final version of this paper.

Shtessel, Yuri B.↗
NASA NTRS1994

Asymptotic Giant Branch stars as a source of short-lived radioactive nuclei in the solar nebula

We carried out a theoretical evaluation of the contribution of Asymptotic Giant Branch (AGB) stars to some short-lived (10(exp 6) less than or equal to Tau-bar less than or equal to 2 x 10(exp 7) yr) isotopes in the Interstellar Medium (ISM) and in the early solar system using stellar model calculations for thermally pulsing evolutionary phases of low-mass stars. The yields of s-process nuclei in the convective He-shell for different neutron exposures tau(sub 0) were obtained, and AGB stars were shown to produce several radioactive nuclei (especially Pd-107, Pb-205, Fe-60, Zr-93, Tc-99, Cs-135, and Hf-182) in diferent amounts. Assuming either contamination of the solar nebula from a single AGB star or models for continuous injection and mixing from many stars into the ISM, we calculate the ratios of radioactive to stable nuclei at the epoch of the Sun's formation. The dilution factor between the AGB ejecta and the early solar system matter is obtained by matching the observed Pd-107/Pd-108 and depends on the value of tau(sub 0). It is found that small masses M(sub He) of He-shell material (10(exp -4)-10(exp -7) solar mass) enriched in s-process nuclei are sufficient to contaminate 1 solar mass of the ISM to produce the Pd-107 found in the early solar system. Predictions are made for all of the other radioactive isotopes. The optimal model to explain several observed radioactive species at different states of the proto-solar nebula involves a single AGB star with a low neutron exposure (tau(sub 0) = 0.03 mbarn(sup -1)) which contaminated the cloud with a dilution factor of M(sub He)/solar mass approximately 1.5 x 10(exp -4). This will also contribute newly synthesized stable s-process nuclei in the amount of approximately 10(exp -4) of their abundances already present in the proto-solar cloud. Variations in the degree of homogenization (approximately 30%) of the injected material may account for some of the small general isotopic anomalies found in meteorites. It is also found that Fe-60 is produced in small but significant quantities that may be sufficient to explain the observations if the time elapsed delta from the contamination of the ISM to the formation of protoplanetary bodies is not higher than delta = 5 x 10(exp 6) yr. If delta is longer, up to 10 x 10(exp 6) yr, this would require the single AGB star to experience enhanced neutron densities (n(sub n) approximately 3 x 10(exp 9)n/cu cm) in the s-processing zone in order to compensate for the branching at Fe-59. The alternative model of long-term continuous ejection of matter from many AGB stars does not appear to match the observations. We also estimate the Al-26 production from the H-shell and find that the Al-26 abundance in the early solar system may be readily explained in a self-consistent manner. Moreover, Al-26 from AGB stars may contribute substantially to the galactic Al-26 gamma-source, while no significant gamma-flux from Co-60 (deriving from Fe-60 decay) is to be expected.

Wasserburg, G. J.↗
DOE OSTI2022

Fusion Blanket and Fuel Cycle Research at PNNL: FY22 Year-end Report

During the reporting period, research at PNNL focused on two tasks within the DOE Fusion Blanket and Fuel Cycle Program. Research on Task 1, Tritium Extraction from Pb-Li and He Using a Vacuum Permeator, focused on atomistic modeling to better understand tritium transport in Pd-coated V vacuum permeators. As a lower cost alternative to Pd permeators, thin coatings of Pd (or other noble metals) can be deposited over a substrate like V. However, the permeation performance of composite metal membranes degrades over time, due to the formation of intermetallics at the coating-substrate interface. Computational studies were performed to better understand tritium transport through these Pd-V intermetallics. The results of the FY22 Pd-V modeling study were recently submitted for publication in Computational Materials Science and presented at the Technology of Fusion Energy conference. Future work in this area will focus on interdiffusion barriers to prevent intermetallic formation that is deleterious to tritium transport. There are opportunities for collaboration with researchers at the Colorado School of Mines, who are manufacturing and testing candidate interdiffusion barriers. Research on Task 3, Solid Breeder Materials, included ion irradiation and post-irradiation characterization of lithium orthosilicate (Li 4 SiO 4 ) and lithium metasilicate (Li 2 SiO 3 ) to improve fundamental understanding of irradiation effects, in combination with atomistic modeling focused on the energetics of He clustering in these two ceramic phases. The results of the study suggested that the Li 4 SiO 4 phase, which is more desirable as a solid breeder due to its higher Li density, was amorphized during ion irradiation while the Li 2 SiO 3 phase appeared to be more resistant to irradiation damage. It is possible that Li loss contributed to the poor irradiation performance of the Li 4 SiO 4 , and some thoughts are provided regarding coatings that could be applied to solid breeders like this to prevent Li loss at elevated temperature while not hindering tritium diffusion. The results of the FY22 ion irradiation study were recently submitted for publication in Journal of Nuclear Materials and presented at the 22nd International Conference on Ion Beam Modification of Materials. Future work in this area will focus on Li-rich ceramics such as Li 5 AlO 4 and Li 8 ZrO 6 that have high Li density and should provide rapid tritium release based on previous work with less Li-rich ceramics.

11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗
DOE OSTI2020

Materials Data on Sr4PdO6 by Materials Project

Sr4PdO6 crystallizes in the trigonal R-3c space group. The structure is three-dimensional. there are two inequivalent Sr2+ sites. In the first Sr2+ site, Sr2+ is bonded in a 6-coordinate geometry to six equivalent O2- atoms. All Sr–O bond lengths are 2.48 Å. In the second Sr2+ site, Sr2+ is bonded in a 8-coordinate geometry to eight equivalent O2- atoms. There are a spread of Sr–O bond distances ranging from 2.62–2.78 Å. Pd4+ is bonded in an octahedral geometry to six equivalent O2- atoms. All Pd–O bond lengths are 2.09 Å. O2- is bonded to five Sr2+ and one Pd4+ atom to form a mixture of distorted face, edge, and corner-sharing OSr5Pd octahedra. The corner-sharing octahedra tilt angles range from 0–63°.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on BaSr3Pd2(OF)4 by Materials Project

BaSr3Pd2(OF)4 crystallizes in the tetragonal P4mm space group. The structure is three-dimensional. Ba2+ is bonded in a body-centered cubic geometry to four equivalent O2- and four equivalent F1- atoms. All Ba–O bond lengths are 2.90 Å. All Ba–F bond lengths are 2.66 Å. There are three inequivalent Sr2+ sites. In the first Sr2+ site, Sr2+ is bonded in a body-centered cubic geometry to four equivalent O2- and four equivalent F1- atoms. All Sr–O bond lengths are 2.72 Å. All Sr–F bond lengths are 2.51 Å. In the second Sr2+ site, Sr2+ is bonded in a body-centered cubic geometry to four equivalent O2- and four equivalent F1- atoms. All Sr–O bond lengths are 2.73 Å. All Sr–F bond lengths are 2.52 Å. In the third Sr2+ site, Sr2+ is bonded in a body-centered cubic geometry to four equivalent O2- and four equivalent F1- atoms. All Sr–O bond lengths are 2.65 Å. All Sr–F bond lengths are 2.55 Å. There are two inequivalent Pd2+ sites. In the first Pd2+ site, Pd2+ is bonded in a square co-planar geometry to four equivalent O2- atoms. All Pd–O bond lengths are 2.08 Å. In the second Pd2+ site, Pd2+ is bonded in a rectangular see-saw-like geometry to four equivalent O2- atoms. All Pd–O bond lengths are 2.07 Å. There are two inequivalent O2- sites. In the first O2- site, O2- is bonded to two equivalent Ba2+, two equivalent Sr2+, and two equivalent Pd2+ atoms to form distorted OBa2Sr2Pd2 octahedra that share corners with two equivalent OBa2Sr2Pd2 octahedra, corners with twelve FBa2Sr2 tetrahedra, edges with two equivalent OBa2Sr2Pd2 octahedra, edges with two FBa2Sr2 tetrahedra, and faces with four equivalent OBa2Sr2Pd2 octahedra. The corner-sharing octahedral tilt angles are 15°. In the second O2- site, O2- is bonded to four Sr2+ and two equivalent Pd2+ atoms to form distorted OSr4Pd2 octahedra that share corners with two equivalent OSr4Pd2 octahedra, corners with twelve FBa2Sr2 tetrahedra, edges with two equivalent OSr4Pd2 octahedra, edges with two FBa2Sr2 tetrahedra, and faces with four equivalent OSr4Pd2 octahedra. The corner-sharing octahedral tilt angles are 3°. There are two inequivalent F1- sites. In the first F1- site, F1- is bonded to two equivalent Ba2+ and two equivalent Sr2+ atoms to form FBa2Sr2 tetrahedra that share corners with twelve OBa2Sr2Pd2 octahedra, corners with four equivalent FBa2Sr2 tetrahedra, edges with two OBa2Sr2Pd2 octahedra, and edges with four equivalent FBa2Sr2 tetrahedra. The corner-sharing octahedra tilt angles range from 6–68°. In the second F1- site, F1- is bonded to four Sr2+ atoms to form FSr4 tetrahedra that share corners with twelve OBa2Sr2Pd2 octahedra, corners with four equivalent FSr4 tetrahedra, edges with two OBa2Sr2Pd2 octahedra, and edges with four equivalent FSr4 tetrahedra. The corner-sharing octahedra tilt angles range from 3–68°.

36 MATERIALS SCIENCE↗