J.K.R. Weber

Materials Development, Inc · R&D

Understanding and controlling liquid‐liquid phase separation in aluminosilicates is crucial for optimizing glass properties. However, the metastable nature of aluminosilicates’ phase separation has made it difficult to study experimentally, and uncertainty persists regarding the compositional and temperature extents of the miscibility gap. Here, we...

To enhance the solubility of orally administered pharmaceuticals, liquid capsules or amorphous tablets are often preferred over crystalline drug products. However, little is known regarding the variation in bonding mechanisms between pharmaceutical molecules in their different disordered forms. In this study, liquid and melt-quenched glassy carbama...

Aluminosilicates (AS) are ubiquitous in ceramics, geology, and planetary science, and their glassy forms underpin vital technologies used in displays, waveguides, and lasers. In spite of this, the nonequilibrium behavior of the prototypical AS compound, mullite (40SiO 2 -60Al 2 O 3 , or AS60), is not well understood. By deeply supercooling mullite-...

Additional 11-B NMR data have been added to Figure 7 of Alderman OLG, Benmore CJ, Reynolds B, Royle B, Feller S, Weber JKR. Liquid fragility maximum in lithium borate glass-forming melts related to the local structure. Int. J. Appl. Glass Sci. 2022. 10.1111/ijag.16611 Unfortunately these data were overlooked at time of publication. The additional...

The structure of liquid lithium pyroborate, Li4B2O5 (J = Li/B = 2), has been measured over a wide temperature range by high‐energy x‐ray diffraction, and compared to that of its glass and borate liquids of other compositions. The results indicate a gradual increase in tetrahedral boron fraction from 3(1)% to 6(1)% during cooling from T = 1271(15)K...

Invited talk slides presented at PNCS XVI, Canterbury, UK, July 12th 2022

Rare-earth titanates form very fragile liquids that can be made into glasses with useful optical properties. We investigate the atomic structure of 83TiO2-17Nd2O3 glass using pair distribution function (PDF) analysis of X-ray and neutron diffraction with double isotope substitutions for both Ti and Nd. Six total structure factors are analyzed (5 ne...

Temperature and density data are in the header, T(r) obtained by sine Fourier Transform of the S(Q) - 1 structure factors using a Qmax = 22.8 inverse angstrom and with ‘Step’ modification function. See main paper and supplementary material for further details.

Amorphous pharmaceuticals often possess a wide range of molecular conformations and bonding arrangements. The x-ray pair distribution function (PDF) method is a powerful technique for the characterization of variations in both intra-molecular and inter-molecular packing arrangements. Here, the x-ray PDF of amorphous Indomethacin is shown to be part...

Invited talk slides presented at Frontiers in Glass II, June 30th 2021

High-energy photon diffraction minimizes many of the corrections associated with laboratory x-ray diffractometers, and enables structure factor measurements to be made over a wide range of momentum transfers. The method edges us closer towards an ideal experiment, in which coordination numbers can be extracted without knowledge of the sample densit...

Comparison of boron coordination in molten LiBO2 from x-ray diffraction (XRD) and x-ray Raman scattering (XRS). References: XRD: Aldeman et al. https://doi.org/10.1063/5.0024457 XRS: Lelong et. al https://doi.org/10.1021/acs.inorgchem.0c02844

Comparison of boron coordination in molten LiBO2 from x-ray diffraction (XRD) and x-ray Raman scattering (XRS). References: XRD: Aldeman et al. https://doi.org/10.1063/5.0024457 XRS: Lelong et. al https://doi.org/10.1021/acs.inorgchem.0c02844

Plain language summary of the article Redox-structure dependence of molten iron oxides, https://www.nature.com/articles/s43246-020-00080-4

The atomic structural arrangements of liquid iron oxides affect the thermophysical and thermodynamic properties associated with the steelmaking process and magma flows. Here, the structures of stable and supercooled iron oxide melts have been investigated as a function of oxygen fugacity and temperature, using x-ray diffraction and aerodynamic levi...

Plain Language Summary and Perspective for the paper "Consequences of sp2–sp3 boron isomerization in supercooled liquid borates" Appl. Phys. Lett. 117, 131901 (2020); https://doi.org/10.1063/5.0024457 https://link.growkudos.com/1f1azh2ihog

Plain Language Summary and Perspective for the paper "Consequences of sp2–sp3 boron isomerization in supercooled liquid borates" Appl. Phys. Lett. 117, 131901 (2020); https://doi.org/10.1063/5.0024457 https://link.growkudos.com/1f1azh2ihog

Time-resolved high-energy synchrotron x-ray total scattering measurements on supercooled molten lithium metaborate (LiBO2) reveal an isomerization reaction involving conversion of trigonal sp2 boron to tetrahedral sp3 boron during quenching and glass formation. Van't Hoff analysis yields an accurate enthalpy change, ΔH = 21(1) kJ mol-1 boron, from...

Incongruent liquid-liquid phase separation is a common phenomenon in molten oxides, but there are few structural studies due to the high temperatures involved ca. >1600oC. Here we present a high-energy x-ray combined small/wide angle scattering (SAXS/WAXS) method that can directly probe non-equilibrium phase diagrams. The Porod exponent in the SAXS...

An aerodynamic conical nozzle levitator (CNL) has been used to measure the melting temperatures of refractory ceramics. The well‐established method of cooling traces has been adapted to allow measurements for air‐sensitive samples using a controlled atmosphere, where the oxygen partial pressure can be adjusted and monitored in real time. In this pa...

The modeling of a loss-of-coolant-accident scenario involving nuclear fuels with FeCrAl cladding materials in consideration to replace a Zircaloy requires knowledge of the thermodynamics of oxidized structures. At temperatures higher than 1500 °C, oxidation of FeCrAl alloys forms (Fe,Cr,Al)3O4 spinels. In situ high-energy X-ray diffraction in a con...

Here we describe a dual detector system for high-energy x-ray, simultaneous, small and wide-angle x-ray scattering (SAXS and WAXS), designed to extract extended-range pair distribution functions (ER-PDF) for disordered materials. The hardware and software provides continuous reciprocal space coverage over atomic to nanometer length-scales. Details...

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High-resolution x-ray pair distribution functions for molten and glassy TeO2 reveal coordination numbers nTeO ≈ 4. However, distinct from the known α-, β- and γ-TeO2 polymorphs, there is considerable short-range disorder such that no clear cutoff distance between bonded and non-bonded interactions exists. We suggest that this is similar to disorder...

Talk slides presented at NCM14, Kobe, Japan, November 2019

The structure of rare-earth titanate melts and glasses of composition 17RE2O3.83TiO2 have been investigated in-situ by aerodynamic levitation with laser heating. Ti K-edge x-ray absorption near-edge structure (XANES) spectroscopy reveals an effect of RE cation size on mean Ti–O coordination numbers (nTiO), which increase from ∼4.8(2) in glass-formi...

High energy X-ray diffraction can be combined with containerless techniques to provide information on the atomic arrangements in glass-forming liquids in stable and metastable regimes. The high incident energies provide bulk diffraction data to high values of scattering vector which enables significantly more robust analysis of the local and medium...

Presentation given at the 25th International Congress on Glass

In the comment on “In Situ Determination of the HfO2‐Ta2O5‐Temperature Phase Diagram up to 3000 °C”, Fedorov praises the outstanding work performed by McCormack et al. Fedorov proposes that although the sketched monotectic phase field satisfies Gibbs phase rule and the lever rule, the curvature between T‐Ta2O5 and L+T‐ Ta2O5 was incorrect, in that...

The pressure-induced structural transformations in metasilicate MSiO3 glass (M=Mg or Ca) on cold-compression from ambient pressure to 17.5 GPa were investigated by neutron diffraction. The structure of the glass recovered to ambient conditions from a pressure of 8.2 or 17.5 GPa was also investigated by neutron or X-ray diffraction. The experimental...

Fig. S1: Comparison of x-ray scattering measurements of molten alumina in oxygen and argon atmospheres. Fig. S2: Comparison of total and partial structure factors and pair distribution functions between amorphous alumina sample 1 and liquid alumina. Fig. S3: Volume, from molecular dynamics, of corundum Al2O3 from ambient temperature through the m...

Additional details of experimental and analysis procedures . Reciprocal space diffraction patterns in the form of structure factors and Q-multiplied interference functions. Additional Ti K-edge XANES spectra over both narrow and broad energy ranges. Akin to Fig. 3 of the Letter, examples of comparisons of molten BaTiO3 and high-pressure liquid CaSi...

Experimental structure factors, as displayed in Fig. S1, are provided.

The structure of molten BaTiO3 has been measured using laser heating, aerodynamic levitation and a combination of neutron diffraction with Ti isotope substitution, x-ray diffraction and spectroscopy. All measurements indicate a Ti–O coordination of nTiO = 4.4(2), far lower than the perovskite or hexagonal crystalline forms. However, nTiO > 4 sugges...

Liquid Al2O3 has been supercooled more than 500 K below its melting point (Tm = 2327 K) using aerodynamic levitation and laser heating techniques. High energy synchrotron x-ray measurements were performed over a temperature range of 1817 ≤ T (K) ≤ 2700 and stroboscopic neutron diffraction at 1984 K and 2587 K. The diffraction patterns have been fit...

This study examines thermal gradients in ceramic oxide spheroids being aerodynamically levitated in a conical nozzle levitator (CNL) system equipped with a CO2 laser (10.6 µm wavelength). The CNL system is a versatile piece of equipment that can easily be coupled with advanced thermophysical and thermochemical measuring devices, such as diffraction...

An overview of the containerless, ultra-high temperature instrumentation on the high energy x-ray beamlines at the Advanced Photon Source is described. It has been implemented for the specific goal of studying crystalline transitions in radioactive materials. The experiments employ laser heating combined with aerodynamic levitation and are designed...

The previously unknown experimental HfO2‐Ta2O5‐temperature phase diagram has been elucidated up to 3000 ˚C using a quadrupole lamp furnace and conical nozzle levitator system equipped with a CO2 laser, in conjunction with synchrotron X‐ray diffraction. These in‐situ techniques allowed the determination of: (i) liquidus, solidus and invariant transf...

The oxidation of boride and carbide-based ultra-high-temperature ceramics is the primary limiting factor for their use as aerodynamic surfaces. Understanding the behaviour of the oxides that can result from oxidation of metal borides and carbides at very high temperatures is essential to optimise and tailor the performance of these materials; yet e...

Abstract Structure and thermodynamics of pure cubic ZrO2 and HfO2 were studied computationally and experimentally from their tetragonal to cubic transition temperatures (2311 and 2530 °C) to their melting points (2710 and 2800 °C). Computations were performed using automated ab initio molecular dynamics techniques. High temperature synchrotron X-ra...

The anisotropic coefficients of thermal expansion and the peritectic transformation of orthorhombic-Hf6Ta2O17 to tetragonal-HfO2 plus liquid at 2250 °C have been studied by in-situ X-ray powder diffraction from room temperature to complete melting (∼2450 °C) in air, using a quadrupole lamp furnace (QLF) and a conical nozzle levitator (CNL) equipped...

Pyrochlore, an ordered derivative of the defect fluorite structure, shows complex disordering behavior as a function of composition, temperature, pressure, and radiation damage. We propose a thermodynamic model to calculate the disordering enthalpies for several RE2Zr2O7 (RE = Sm, Eu, Gd) pyrochlores from experimental site distribution data obtaine...

Invited talk slides presented at the 2018 Glass and Optical Materials Division (GOMD) Meeting of the American Ceramic Society, San Antonio, TX, USA, 23rd May 2018

Plot comparing x-ray S(Q) for amorphous tantala with and without residual substrate Bragg peaks masked. Plots comparing neutron diffraction data with and without Fourier filtering. Plots comparing x-ray data from melts in different gases. Plots comparing x-ray data obtained at different incident energies, including small-angle x-ray scattering. Com...

The structure factors of molten Ta2O5 and Nb2O5 have been measured by high-energy x-ray and pulsed neutron diffraction. These are compared to transmission-mode x-ray diffraction through a self-supported 15 μm ion-beam-sputtered amorphous tantala film. Atomistic models derived from the diffraction data by means of empirical potential structure refin...

Borate melts containing < 20 mol% Na2O have been studied using high-energy synchrotron x-ray diffraction. Temperature dependencies of the mean B–O bond lengths are shown to vary strongly with soda content, by comparison to previous measurements on liquid B2O3 and Na2B4O7. Whereas in liquid B2O3 linear thermal expansion of the BØ3 units is observed,...

In the exceedingly rare event of nuclear reactor core meltdown, uranium dioxide fuel reacts with Zircaloy cladding to produce eutectic melts which can subsequently be oxidized by coolant/moderator water. Oxidized corium liquids in the xUO2·(100 − x)ZrO2 system were produced via laser melting of UO2-ZrO2 mixtures to temperatures in excess of 3000 K....

This file is updated with additional figures, compared to the original file uploaded here on 5/2/2018. The file now correctly conforms with the published supplemental material.

X-ray structure factor, S(Q) - 1, for molten 21UO2-79ZrO2 at T = 2651 K, in 4%H2 : UHP argon atmosphere.

X-ray structure factor, S(Q) - 1, for molten 20UO2-80ZrO2 at T = 2885 K, in UHP argon atmosphere.

Microsoft Word .docx version of the supplementary figures and tables.

X-ray structure factor, S(Q) - 1, for molten 4UO2-96ZrO2 at T = 2782 K, in UHP argon atmosphere.