scholarly journals Sparse ab initio x-ray transmission spectrotomography for nanoscopic compositional analysis of functional materials

2021 ◽  
Vol 7 (24) ◽  
pp. eabf6971
Author(s):  
Zirui Gao ◽  
Michal Odstrcil ◽  
Sebastian Böcklein ◽  
Dennis Palagin ◽  
Mirko Holler ◽  
...  
Keyword(s):  
Local Structure ◽  
Compositional Analysis ◽  
Functional Materials ◽  
Atomic Level ◽  
Complex Geometries ◽  
Phosphorus Oxide ◽  
X Ray ◽  
Vanadium Phosphorus Oxide ◽  
X Ray Computed ◽  
Industrial Use

The performance of functional materials is either driven or limited by nanoscopic heterogeneities distributed throughout the material’s volume. To better our understanding of these materials, we need characterization tools that allow us to determine the nature and distribution of these heterogeneities in their native geometry in 3D. Here, we introduce a method based on x-ray near-edge spectroscopy, ptychographic x-ray computed nanotomography, and sparsity techniques. The method allows the acquisition of quantitative multimodal tomograms of representative sample volumes at sub–30 nm half-period spatial resolution within practical acquisition times, which enables local structure refinements in complex geometries. To demonstrate the method’s capabilities, we investigated the transformation of vanadium phosphorus oxide catalysts with industrial use. We observe changes from the micrometer to the atomic level and the formation of a location-specific defect so far only theorized. These results led to a reevaluation of these catalysts used in the production of plastics.

scholarly journals Local Structure and Dynamics of Functional Materials Studied by X-ray Absorption Fine Structure

Symmetry ◽  
2021 ◽  
Vol 13 (8) ◽  
pp. 1315
Author(s):  
Takafumi Miyanaga
Keyword(s):  
Fine Structure ◽  
Local Structure ◽  
Chemical Reactivity ◽  
Functional Materials ◽  
X Ray ◽  
Structure And Dynamics ◽  
Absorption Fine ◽  
Structure Phase Transition ◽  
Local Electronic Structure ◽  
X Ray Absorption

X-ray absorption fine structure (XAFS) is a powerful technique used to analyze a local electronic structure, local atomic structure, and structural dynamics. In this review, I present examples of XAFS that apply to the local structure and dynamics of functional materials: (1) structure phase transition in perovskite PbTiO3 and magnetic FeRhPd alloys; (2) nano-scaled fluctuations related to their magnetic properties in Ni–Mn alloys and Fe/Cr thin films; and (3) the Debye–Waller factors related to the chemical reactivity for catalysis in polyanions and ligand exchange reaction. This study shows that the local structure and dynamics are related to the characteristic function of the materials.

scholarly journals Influence of the geometric structure on the V L3 near edge X-ray absorption fine structure from vanadium phosphorus oxide catalysts

2002 ◽  
Vol 125 (2) ◽  
pp. 79-87 ◽  
Author(s):  
Michael Hävecker ◽  
Axel Knop-Gericke ◽  
Ralf W Mayer ◽  
Martin Fait ◽  
Hendrik Bluhm ◽  
...  
Keyword(s):  
Fine Structure ◽  
Geometric Structure ◽  
Oxide Catalysts ◽  
Phosphorus Oxide ◽  
X Ray ◽  
Absorption Fine ◽  
Vanadium Phosphorus Oxide ◽  
X Ray Absorption

Standards for Evaluating the Influence of Materials on the Performance of X-Ray Computed Tomography in Measuring Geometric Variability

2020 ◽  
Author(s):  
Craig M. Shakarji ◽  
Vijay Srinivasan ◽  
Vincent D. Lee ◽  
Meghan Shilling ◽  
Bala Muralikrishnan
Keyword(s):  
Computed Tomography ◽  
Standardized Tests ◽  
Measuring System ◽  
Error Sources ◽  
X Ray ◽  
Optical Instruments ◽  
X Ray Computed ◽  
Industrial Use ◽  
Source Of Error ◽  
Geometric Measurement

Abstract The industrial use of X-ray Computed Tomography (known briefly as XCT, or sometimes simply as CT) is on the rise because a single XCT scan can measure an arbitrary number of features, and XCT instruments can measure features inaccessible to contact or optical instruments — even features that are completely encased in material. This makes XCT a natural metrological companion to additive manufacturing where internal features (e.g., lattice structures) can be produced. But this advantage of being able to measure through material is somewhat mitigated by the fact that the obstructing material has a strong influence on the geometric measurement and is a dominant source of error. This problem is addressed by two emerging documentary standards in ASME and ISO (International Organization for Standardization). These documents define standardized tests for metrological accuracies of an XCT system, where accuracies — now unambiguously defined — can be expressed as Maximum Permissible Errors (MPEs). These tests rely on calibrated artifacts that are designed to reveal various XCT error sources when the system measures these artifacts in prescribed manners. This paper gives the general philosophy behind Coordinate Measuring System standards and then applies them to XCT systems in particular. Rationale is given for the artifact choices contained within these standards, with particular emphasis on material effects, and clarifies the metrological coverage of these standards.

X-ray microprobe for materials science

1994 ◽  
Vol 52 ◽  
pp. 56-57
Author(s):  
G.E. Ice
Keyword(s):  
Crystallographic Orientation ◽  
Local Structure ◽  
Materials Science ◽  
Chemical Information ◽  
X Ray Diffraction ◽  
Ray Optics ◽  
X Ray ◽  
Novel Materials ◽  
New Information ◽  
Elemental Sensitivity

The increasing availability of synchrotron x-ray sources has stimulated the development of advanced hard x-ray (E≥5 keV) microprobes. With new x-ray optics these microprobes can achieve micron and submicron spatial resolutions. The inherent elemental and crystallographic sensitivity of an x-ray microprobe and its inherently nondestructive and penetrating nature will have important applications to materials science. For example, x-ray fluorescent microanalysis of materials can reveal elemental distributions with greater sensitivity than alternative nondestructive probes. In materials, segregation and nonuniform distributions are the rule rather than the exception. Common interfaces to whichsegregation occurs are surfaces, grain and precipitate boundaries, dislocations, and surfaces formed by defects such as vacancy and interstitial configurations. In addition to chemical information, an x-ray diffraction microprobe can reveal the local structure of a material by detecting its phase, crystallographic orientation and strain.Demonstration experiments have already exploited the penetrating nature of an x-ray microprobe and its inherent elemental sensitivity to provide new information about elemental distributions in novel materials.

High Spatial Resolution Compositional Analysis at Interfaces

1980 ◽  
Vol 38 ◽  
pp. 356-359
Author(s):  
John B. Vander Sande ◽  
Thomas F. Kelly ◽  
Douglas Imeson
Keyword(s):  
Electron Microscope ◽  
High Spatial Resolution ◽  
Compositional Analysis ◽  
Scanning Transmission Electron Microscope ◽  
Thin Specimen ◽  
X Ray ◽  
Volume Of Interest ◽  
Transmission Electron ◽  
Scanning Transmission ◽  
Electron Energy Loss

In the scanning transmission electron microscope (STEM) a fine probe of electrons is scanned across the thin specimen, or the probe is stationarily placed on a volume of interest, and various products of the electron-specimen interaction are then collected and used for image formation or microanalysis. The microanalysis modes usually employed in STEM include, but are not restricted to, energy dispersive X-ray analysis, electron energy loss spectroscopy, and microdiffraction.

X-Ray Computed Tomography of Ultralightweight Metals

1999 ◽  
Vol 11 (1) ◽  
pp. 199-211
Author(s):  
J. M. Winter ◽  
R. E. Green ◽  
A. M. Waters ◽  
W. H. Green
Keyword(s):  
Computed Tomography ◽  
X Ray ◽  
X Ray Computed

Determination of reservoir rock residual water using X-ray computed microtomography

2018 ◽  
pp. 38-42 ◽  
Author(s):  
I.V. Yazynina ◽  
◽  
E.V. Shelyago ◽  
A.A. Abrosimov ◽  
N.E. Grachev ◽  
...  
Keyword(s):  
Reservoir Rock ◽  
Residual Water ◽  
X Ray ◽  
Computed Microtomography ◽  
X Ray Computed

Application of In Situ X-ray Absorption Spectroscopy to Study Dilute Chromium Ions in a Molten Chloride Salt

2019 ◽  
Author(s):  
Jisue Moon ◽  
Carter Abney ◽  
Dmitriy Dolzhnikov ◽  
James M. Kurley ◽  
Kevin A. Beyer ◽  
...  
Keyword(s):  
Absorption Spectroscopy ◽  
Local Structure ◽  
Chloride Salt ◽  
X Ray ◽  
Molten Chloride ◽  
Stable Species ◽  
Higher Temperature ◽  
Cr Concentration ◽  
X Ray Absorption

The local structure of dilute CrCl<sub>3</sub> in a molten MgCl<sub>2</sub>:KCl salt was investigated by <i>in situ</i> x-ray absorption spectroscopy (XAS) at temperatures from room temperature to 800<sup>o</sup>C. This constitutes the first experiment where dilute Cr speciation is explored in a molten chloride salt, ostensibly due to the compounding challenges arising from a low Cr concentration in a matrix of heavy absorbers at extreme temperatures. CrCl<sub>3</sub> was confirmed to be the stable species between 200 and 500<sup>o</sup>C, while mobility of metal ions at higher temperature (>700<sup>o</sup>C) prevented confirmation of the local structure.

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