Synchrotron X-ray Study Research Articles

Relationship of interface structure to the dynamics of selective lanthanide extraction

Recent synchrotron X-ray studies have revealed a variety of specific ion effects in the structures formed by lanthanides and surfactants at air-water and solvent-water interfaces. However, the relevance of the interfacial structure to extraction and selective separation processes has been unclear. We have studied solvent extraction from aqueous solutions containing lanthanide ions to organic solvents containing model extractants, and correlated the results to the interfacial structure. The selectivity, extraction rates and extraction efficiencies are consistent with the postulate that when hydrophobic bilayers form at the interface, there is faster and better extraction. Further, selectivity during extraction from mixtures is enhanced when there is less extractant than needed for complete extraction of all the ions present.

Recent advances in synchrotron X-ray studies of the atomic structures of metal alloys in liquid state

Research into the atomic structures of metal materials in the liquid state, their dynamic evolution versus temperature until the onset of crystal nucleation has been a central research topic in condensed matter physics and materials science for well over a century. However, research and basic understanding of the atomic structures of liquid metals are far less than those in the solid state of the same compositions. This review serves as a condensed collection of the most important research literature published so far in this field, providing a critical and focused review of the historical research development and progress in this field since the 1920s. In particular, the development of powerful synchrotron X-ray sources and the associated experimental techniques and sample environments for studying in-situ the atomic structures of different metallic systems. The key findings made in numerous pure metals and metallic alloy systems are critically reviewed and discussed with the focus on the results and new understandings of structural heterogeneities found inside a bulk liquid, at the liquid surface or liquid-solid interface. The possible future directions of research and development on the most advanced experimental and modeling techniques are envisaged and briefly discussed as well.

Control of nano-cavitation in semi-crystalline polymer nanocomposites during uniaxial tension: In situ synchrotron X-ray study

The cavitation behavior of polypropylene-silica (PP-silica) and high density polyethylene-silica (HDPE-silica) composites with varying silica content during uniaxial tension was investigated via in situ X-ray techniques. The introduction of silica was found to significantly influence the mechanical properties of the materials. Small-angle X-ray scattering (SAXS) was employed to determine the cavitation onset strain and to observe the evolution of cavity structures. Through model fitting, the size evolution of nanoscale cavities at the onset of cavitation was quantitatively characterized. Scanning electron microscopy (SEM) was utilized to examine the morphology before and after stretching, revealing that cavity structures primarily resulted from internal defects in the polymer matrix and interfacial debonding between silica and the polymer. The long axis of the nanoscale cavities at the onset of cavitation was perpendicular to the tensile direction, and further deformation led to the coalescence into micron-sized cavities with the long axis parallel to the tensile direction. Wide-angle X-ray scattering (WAXS) was used to characterize the microscale deformation process of crystals, showing that during stretching, the lamellae reoriented with the angle between their normal direction and the tensile direction gradually decreasing. Several sets of transition strains representing the plastic deformation were used to compare the microscale and macroscale deformation, elucidating the sequence and differentiation between crystal plastic deformation, cavitation, and yield in the two polymer materials. Intriguingly, both PP-silica and HDPE-silica composites exhibited optimal silica additions and initial structural parameters for regulating cavitation behavior. These findings offer significant guidance for the control of internal structures in porous separators in industrial production.

Synchrotron X-ray study of intrinsically disordered and polyampholytic Tau 4RS and 4RL under controlled ionic strength.

Aggregated and hyperphosphorylated Tau is one of the pathological hallmarks of Alzheimer's disease. Tau is a polyampholytic and intrinsically disordered protein (IDP). In this paper, we present for the first time experimental results on the ionic strength dependence of the radius of gyration (Rg) of human Tau 4RS and 4RL isoforms. Synchrotron X-ray scattering revealed that 4RS Rg is regulated from 65.4 to 58.5Å and 4RL Rg is regulated from 70.9 to 57.9Å by varying ionic strength from 0.01 to 0.592M. The Rg of 4RL Tau is larger than 4RS at lower ionic strength. This result provides an insight into the ion-responsive nature of intrinsically disordered and polyampholytic Tau, and can be implicated to the further study of Tau-Tau and Tau-tubulin intermolecular structure in ionic environments.

All-solid-state sodium-ion batteries operating at room temperature based on NASICON-type NaTi2(PO4)3 cathode and ceramic NASICON solid electrolyte: A complete in situ synchrotron X-ray study

All-solid-state sodium-ion batteries that work at ambient temperature are a potential approach for large-scale energy storage systems. Nowadays, ceramic solid electrolytes are gaining attention because of their good ionic conductivity and excellent mechanical and chemical stabilities. Furthermore, a good interface between electrode and solid electrolyte is also required to achieve successful cell performances. In this work, sintered ceramic layer electrolyte Na3.16Zr1.84Y0.16Si2PO12, with high ionic conductivity (0.202 mS/cm at room temperature), are prepared by using uniaxial pressing followed by a sintering process. The conductive carbon coated NASICON material (NaTi2(PO4)3/C) exhibits, as cathode material, enhanced rate capability and stability for sodium ion batteries for high carbon (18.95 %) coated sample. At C/10, the optimized cathode (with higher carbon content) achieves a remarkable initial discharge capacity of 107.3 mAh/g (reversible capacity of 101.4 mAh/g), a sufficient rate capability up to a rate of 10C, and a long cycle life (capacity retention of 58% after 950 cycles). The one-stage reversible biphasic reaction mechanism and potential-dependent structure–property of NaTi2(PO4)3 can be explained by employing in situ X-ray synchrotron method. Sequential Rietveld refinements of the in situ data show the evolution of the Na-poor NaTi2(PO4)3 and Na-rich Na3Ti2(PO4)3 phase fractions (wt%), unit cell characteristics, and unit cell volume. The design of an all-solid-state sodium ion half-cell with a NaTi2(PO4)3/C cathode and a Na3.16Zr1.84Y0.16Si2PO12 solid-state electrolyte interface results in stable capacity of 83.6 mAh/g at C/10 and excellent reversible capacity at high C-rate. The results show that sintered NASICON-based electrolytes can significantly contribute for the fabrication of all-solid-state sodium-ion battery due to the superior conductivity and stability.

Synchrotron X-ray Studies of the Structural and Functional Hierarchies in Mineralised Human Dental Enamel: A State-of-the-Art Review.

Hard dental tissues possess a complex hierarchical structure that is particularly evident in enamel, the most mineralised substance in the human body. Its complex and interlinked organisation at the Ångstrom (crystal lattice), nano-, micro-, and macro-scales is the result of evolutionary optimisation for mechanical and functional performance: hardness and stiffness, fracture toughness, thermal, and chemical resistance. Understanding the physical-chemical-structural relationships at each scale requires the application of appropriately sensitive and resolving probes. Synchrotron X-ray techniques offer the possibility to progress significantly beyond the capabilities of conventional laboratory instruments, i.e., X-ray diffractometers, and electron and atomic force microscopes. The last few decades have witnessed the accumulation of results obtained from X-ray scattering (diffraction), spectroscopy (including polarisation analysis), and imaging (including ptychography and tomography). The current article presents a multi-disciplinary review of nearly 40 years of discoveries and advancements, primarily pertaining to the study of enamel and its demineralisation (caries), but also linked to the investigations of other mineralised tissues such as dentine, bone, etc. The modelling approaches informed by these observations are also overviewed. The strategic aim of the present review was to identify and evaluate prospective avenues for analysing dental tissues and developing treatments and prophylaxis for improved dental health.

Understanding SiOC atomic structures via synchrotron X-ray and reactive force field potential studies

Silicon oxycarbide (SiOC) is a unique system that can generate various compositions and microstructures via different polymeric precursors and pyrolysis conditions. However, understanding of the atomic structure evolution, such as cluster formation, phase evolution, and atomic coordination, is lacking. In this study, cluster evolution and atomic coordination for different SiOC ceramics pyrolyzed at 1200 °C and 1500 °C were investigated by high energy X-ray diffraction (HE-XRD) and radial distribution function (RDF) analysis. A new Reactive Force Field (ReaxFF) molecular dynamics modeling approach was developed to understand nanocluster separation and early-stage atomic radial coordination. For the first time, we demonstrate that orthorhombic SiO2 forms and converts to growth resistant amorphous SiO2. Cubic β-SiC also forms at lower temperatures than reported, along with a minor amount of hexagonal SiC that has never been reported. The RDF data support such phase evolution understanding. ReaxFF simulation provides direct data on atomic mixing, elemental separation, and effects of precursor molecular structures and compositions, especially in the early stage of the pyrolysis. The simulated RDF data complement the experimental data, revealing the significant presence of C–H bonds along with Si–O and C–C bonds.

Cavitation behavior of polypropylene/polyethylene multilayer films during uniaxial tensile deformation: In-situ synchrotron X-ray study

The cavitation of melt-coextruded multilayer films of alternated polypropylene (PP) and polyethylene (PE) during the uniaxial tensile deformation has been investigated. The initiation and evolution of cavities and the relationship between cavitation and plastic deformation have been studied via in-situ SAXS and WAXS techniques. The critical strain for the initiation of cavitation (εcav), crystal shear (εCSh), and yield (εyield) have been estimated from the in-situ experiments. The results show that the sequence of deformation is crystal shear, cavitation and yield, i.e. εCSh<εcav<εyield, indicating that crystal plastic deformation occurs before the cavitation and yield. Additionally, the layer numerosity and annealing temperature (Tanneal) have been discovered to not only modify the mechanical behavior but also regulate cavitation by changing the initial microstructure. The samples with less layer numerosity and high Tanneal improve the macroscopic mechanical strength, whereas the increase of layer numerosity can reduce the stress of cavitation onset (σcav) and retard the onset of cavitation onset (high εcav value). The current study is significant in elucidating the internal mechanism of stretch-induced cavitation behavior in multilayer films.

Understanding the Structural Phase Transitions in Na3V2(PO4)3 Symmetrical Sodium-Ion Batteries Using Synchrotron Based X-Ray Techniques

Sodium ion batteries (SIBs) are the promising candidate for large scale applications due to their high abundance and low cost.The symmetrical SIBs (similar cathode and anode configuration) are highly promising as they exhibit negligible volume changes during the charge/discharge process and making SIBs highly stable. Several NASICON (sodium superionic conductor) have high potential towards symmetrical SIBs due to presence of multi-redox reactions in both anodic and cathodic regions. Na3V2(PO4)3 (NVP) has been found to be appeal for symmetrical SIB systems due to presence of flat voltage profile, multi-redox with a single transition metal, and a large working voltage difference between anodic and cathodic regions can greatly improve the output of the NVP symmetrical cell. However, the phase transitions associated during the electrochemical reaction in the symmetrical NVP cells are not widely studied. The synchrotron X-ray studies in NVP symmetrical cells confirms the redox reaction involving ≈2 moles of Na+ reaction instead of 1 mole of Na+ reaction. The in-situ X-ray diffraction and X-ray absorption spectroscopy during the electrochemical cycling confirms the reversible formation of Na5V2(PO4)3 phase in the anode and NaV2(PO4)3 phase in the cathode. The charge storage process in NVP cathode region is through V3+/V4+ redox, and charge storage process in NVP anode region is through V3+/V2+ redox. The 2 moles sodium-ion storage process can make a discharge capacity of ≈99 mAh g−1, increasing the energy output of the symmetrical NVP.

Crystallographic and shape preferred orientation producing anisotropy in slates from Northern Spain

Slates are common metasedimentary rocks in the Iberian Peninsula, ranging in deposition age from Proterozoic to Ordovician. Spain is currently the primary producer of high-quality slate products. The excellent cleavage is related to microstructures with very strong preferred orientation of white mica and chlorite. In this study we explore preferred orientation of eleven slates and one phyllite of different composition and metamorphic grade from Northern Spain with high energy synchrotron X-ray diffraction and study microstructures with scanning electron microscopy. While phyllosilicates display high crystallographic and shape preferred orientation, quartz, with also highly flattened grains, has in most samples a random crystallographic orientation. The microstructural and texture data are used to model anisotropic seismic properties with a self-consistent method and to explore the influence of crystal shapes on elastic anisotropy. Anisotropy for these slates is very high compared with gneiss and shale and, due to its prevalence, slate anisotropy contributes significantly to seismic anisotropy in the upper crust.

Synchrotron X-ray study of electromigration, whisker growth, and residual strain evolution in a Sn Blech structure

Synchrotron X-ray analysis of the Sn electromigration behavior and Sn whisker growth in a Blech structure using nano-X-ray fluorescence microscopy and white beam Laue nanodiffraction was conducted. Sn depletion at the cathode and whisker/extrusion formation at the anode were characterized in-situ, and the results obeyed the electromigration kinetics. This electromigration scenario gradually decayed because of the counterbalance between electron wind force and back stress. White beam Laue nanodiffraction analysis showed that a noticeable compressive deviatoric stress in the direction of electron flow built up at the anode of Sn strips, particularly in the roots of Sn whiskers, confirming that electromigration-induced atomic accumulation occurred downstream in a strip and that Sn whiskering was closely related to internal stress resulting from atomic accumulation in confined segments. Finally, a theoretical model based on fundamental electromigration theory revealed that Sn diffused predominately through lattice and grain boundary paths at Sn homologous temperature of 0.6.

Revealing structure-selectivity correlations in pulsed CO2 electrolysis via time-resolved operando synchrotron X-ray studies

Revealing structure-selectivity correlations in pulsed CO2 electrolysis via time-resolved operando synchrotron X-ray studies

Operando synchrotron X-ray studies of MnVOH@SWCNT nanocomposites as cathodes for high-performance aqueous zinc-ion batteries

MnVOH@SWCNTs shows a high capacity up to 381 mA h g−1 over 300 cycles. Operando XANES confirms the change in oxidation states and operando XRD shows the reversible change in the crystal structure during the cycling process.

Loading dependence and tension–compression asymmetry of deformation twinning in textured Mg-3Al-1Zn alloy: A multiscale synchrotron X-ray study

We investigate deformation dynamics in a textured magnesium alloy under uniaxial tension and compression along two different directions. The loading axis (LA) is either parallel or perpendicular to the normal direction (ND), referred to as LA∥ND tension/compression and LA⊥ND tension/compression, respectively. Stress−strain curves are measured simultaneously with X-ray diffraction and strain field mapping via synchrotron X-ray digital image correlation. Massive {101̄2} extension twins are observed in the LA∥ND tension and LA⊥ND compression specimens. The growth rate of tension-induced twins is lower than that of compression-induced twins, likely because the pyramidal 〈c+a〉 slips accommodate partial deformation along the c-axis in the LA∥ND tension specimen. Both the tension- and compression-induced deformation twins can slow down the process of strain localization, and thus an increase in strain hardening rate as well as the anisotropy in plastic deformation. The plastic strain ratios depend on strain localization and the relative orientation of the loading direction with respect to the basal texture, and are much larger in tension than in compression.

Shear-Induced Ordering of Nanopores and Instabilities in Concentrated Surfactant Mesh Phases.

Mixed surfactant systems with strongly bound counterions show many interesting phases such as the random mesh phase consisting of a disordered array of defects (water-filled nanopores in the bilayers). The present study addresses the non-equilibrium phase transition of the random mesh phase under shear to an ordered mesh phase with a high degree of coherence between nanopores in three dimensions. In situ small-angle synchrotron X-ray study under different shear stress conditions shows sharp Bragg peaks in the X-ray diffraction, successfully indexed to the rhombohedral lattice with R3̅m space group symmetry. The ordered mesh phase shows isomorphic twinning and buckling at higher shear stress. Our experimental studies bring out rich non-equilibrium phase transitions in concentrated cationic surfactant systems with strongly bound counterions hitherto not well explored and provide motivation for a quantitative understanding.

A New Superconducting 3R-WS2 Phase at High Pressure.

High-pressure investigation has been shown to be of paramount significance for changing the conventional lattice or bringing fascinating properties, especially inducing superconducting phases. Here we studied the application of pressure to the recently synthesized 2M-WS2 with the record Tc (8.8 K) among transition metal dichalcogenides (TMDs) at ambient pressure by electrical resistance investigations, synchrotron X-ray studies, and theoretical calculations. Tc in the initial 2M-WS2 dropped from the maximum to become undetected, accompanied by a phase transition into a semiconductor, 3R-WS2, at 15 GPa. The successive metallization and superconducting transitions in 3R-WS2 were observed at 48.8 GPa with Tc ≈ 2.5 K. This is the first experimental case in which superconductivity has been realized in the 3R phase among TMDs. We propose that the degradation of superconductivity in 2M-WS2 and the reemergence of superconductivity in 3R-WS2 are mainly attributable to changes in the density of states near the Fermi surface driven by the interlayer coupling.

TEM and Synchrotron X-ray Study of the Evolution of Phases Formed During Bonding of IN718/Al/IN718 Couples by TLPB

TEM and Synchrotron X-ray Study of the Evolution of Phases Formed During Bonding of IN718/Al/IN718 Couples by TLPB

An operando spatially resolved study of alkaline battery discharge using a novel hyperspectral detector and X-ray tomography.

An experimental technique is described for the collection of time-resolved X-ray diffraction information from a complete commercial battery cell during discharging or charging cycles. The technique uses an 80 × 80 pixel 2D energy-discriminating detector in a pinhole camera geometry which can be used with a polychromatic X-ray source. The concept was proved in a synchrotron X-ray study of commercial alkaline Zn-MnO2 AA size cells. Importantly, no modification of the cell was required. The technique enabled spatial and temporal changes to be observed with a time resolution of 20 min (5 min of data collection with a 15 min wait between scans). Chemical changes in the cell determined from diffraction information were correlated with complementary X-ray tomography scans performed on similar cells from the same batch. The clearest results were for the spatial and temporal changes in the Zn anode. Spatially, there was a sequential transformation of Zn to ZnO in the direction from the separator towards the current collector. Temporally, it was possible to track the transformation of Zn to ZnO during the discharge and follow the corresponding changes in the cathode.

In Situ Synchrotron X-ray Study of the Mechanical Properties of Pure Mg Produced by Powder Metallurgy

In this study, in situ synchrotron X-ray experiments with wide-angle X-ray scattering (WAXS) and small-angle X-ray scattering (SAXS) detectors were performed on two pure magnesium materials produced by powder metallurgy. According to SAXS analysis, each of the two materials has a porosity of less than 0.5%. Line broadening analysis was performed on diffraction patterns collected by WAXS to analyze the dislocation evolution during material deformation. In both materials, &lt;a&gt;-type dislocation activities dominate the tensile deformation. The influence of grain size and texture on the different tensile behaviors of these two materials is also discussed.

High-energy synchrotron x-ray study of deformation-induced martensitic transformation in a neutron-irradiated Type 316 stainless steel

An unusual tensile deformation behaviour in the form of a propagating band along the sample gauge was observed in two neutron-irradiated 316 stainless steel samples during room-temperature tests, leading to a combination of high strength and high ductility. These bands were not observed in an unirradiated counterpart. With the help of in situ high-energy synchrotron x-ray diffraction, the phase-specific crystal information was tracked at different deformation levels in each sample. Post-irradiation and post-deformation samples were examined using electron microscopy to characterize various microstructural features. All samples displayed a deformation-induced martensitic phase transformation, which was identified as a second strain-hardening mechanism accompanying the dislocation hardening. The deformation-induced martensitic transformation was rationalized by the effect of applied stress on the effective martensite start temperature. The results showed that the irradiation did not alter the dislocation hardening and the martensitic transformation mechanisms, but the increased yield strength in irradiated materials facilitated the localized phase transformation at the onset of plastic deformation, in contrast to the unirradiated material which required pre-straining. The hardening effect of the martensitic transformation reduced the tendency towards necking and mitigated the loss of ductility in the irradiated material by carrying the deformation in the form of a propagating band. Despite the beneficial effect from the martensitic transformation, this study indicates that this mechanism cannot not be activated at typical operating temperatures of nuclear reactors.