A5055307465- X-ray Diffraction in Crystallography
- Advancements in Solid Oxide Fuel Cells
- Radioactive element chemistry and processing
- Paleontology and Stratigraphy of Fossils
- Hydrocarbon exploration and reservoir analysis
- Advanced X-ray Imaging Techniques
- Electron and X-Ray Spectroscopy Techniques
- Catalytic Processes in Materials Science
- X-ray Spectroscopy and Fluorescence Analysis
- Electronic and Structural Properties of Oxides
- High Entropy Alloys Studies
- Advanced X-ray and CT Imaging
- Additive Manufacturing Materials and Processes
- Nuclear Materials and Properties
- Phase-change materials and chalcogenides
- Semiconductor materials and devices
- Geological and Geochemical Analysis
- Advanced Electron Microscopy Techniques and Applications
- Enhanced Oil Recovery Techniques
- Ion-surface interactions and analysis
- Magnetic and transport properties of perovskites and related materials
- Electrocatalysts for Energy Conversion
- Advancements in Battery Materials
- Additive Manufacturing and 3D Printing Technologies
- Glass properties and applications
Paul Scherrer Institute
2016-2024
Swiss Light Source
2016-2024
University of California, Santa Cruz
2024
CEA Grenoble
2014-2020
CEA LETI
2014-2020
Institut polytechnique de Grenoble
2014-2020
Commissariat à l'Énergie Atomique et aux Énergies Alternatives
2013-2020
Université Grenoble Alpes
2014-2019
University of Monterrey
2016-2018
Universidade Federal do Rio Grande do Sul
2010-2015
In metallurgy, mechanical deformation is essential to engineer the microstructure of metals and tailor their properties. However, this practice inapplicable near-net-shape metal parts produced by additive manufacturing (AM), since it would irremediably compromise carefully designed geometries. work, we show how circumvent limitation controlling dislocation density thermal stability a steel alloy laser powder bed fusion (LPBF) technology. We that manipulating alloy's solidification structure,...
We present combined in situ X-ray diffraction and high-speed imaging to monitor the phase evolution upon cyclic rapid laser heating cooling mimicking direct energy deposition of Ti-6Al-4V real time. Additive manufacturing industrially relevant alloy is known create a multitude phases microstructures depending on processing technology parameters. Current setups are limited by an averaged measurement through solid liquid parts. In this work combination micro-focused intense beam, fast detector...
Laser based additive manufacturing allows to build a designed shape layer-by-layer, offering versatility and flexibility many metallurgical sectors. The fast cooling rates repeated heat cycles depending on the laser scanning parameters are not easily measurable with conventional methods. Thus, advanced predictive computational simulations, required reduce trial error lead time, difficult validate. A newly developed in operando X-ray diffraction device implemented at synchrotron beamline,...
Abstract Since its commercial introduction three-quarters of a century ago, fluid catalytic cracking has been one the most important conversion processes in petroleum industry. In this process, porous composites composed zeolite and clay crack heavy fractions crude oil into transportation fuel petrochemical feedstocks. Yet, over time activity these composite particles decreases. Here, we report on ptychographic tomography, diffraction, fluorescence as well electron microscopy measurements,...
The discovery of Li-containing transition-metal (TM) oxides has attracted broad interest and triggered intensive studies on these as cathodes for lithium-ion batteries over decades. Unfortunately, a clear picture how Li/TM/O ions are transported electrons transferred during the synthesis compounds is still missing, especially when cubic close-packed (ccp) anion sublattices involved, it case spinel, layered, or rock-salt systems. In present study, series layered Li(Ni,Co,Mn)O2 were chosen...
When Ti-6Al-4V is processed by laser powder bed fusion (L-PBF), acicular martensitic α'-Ti grains are formed within the columnar prior β-Ti grains, resulting in inferior mechanical properties. The application of blended powders L-PBF enables to tailor microstructures and obtain a mixture α' + β phases. In this work, we demonstrate an effective method engineer phase fraction manufactured Ti alloy using consisting 3 wt% Fe particles. By varying parameters, as-built transit from dominated...
We report a synthesis method for highly monodisperse Cu–Pt alloy nanoparticles. Small and large particles with Cu/Pt ratio of 1:1 can be obtained through colloidal at 300 °C. The fresh have Pt-rich surface Cu-rich core converted into an intermetallic phase after annealing 800 °C under H2. First, we demonstrated the stability redox conditions 400 °C, as prevents substantial oxidation Cu. Then, combination in situ scanning transmission electron microscopy, X-ray absorption spectroscopy, CO...
We report on an element-selective study of the fate charge carriers in photoexcited inorganic CsPbBr3 and CsPb(ClBr)3 perovskite nanocrystals toluene solutions using time-resolved X-ray absorption spectroscopy with 80 ps time resolution. Probing Br K-edge, Pb L3-edge, Cs L2-edge, we find that holes valence band are localized at atoms, forming small polarons, while electrons appear as delocalized conduction band. No signature either electronic or structural changes is observed L2-edge. The...
Fluid catalytic cracking is a chemical conversion process of industrial scale. This process, utilizing porous catalysts composed clay and zeolite, converts heavy crude-oil fractions into transportation fuel petrochemical feedstocks. Among other factors iron-rich reactor feedstream impurities cause these catalyst particles to permanently deactivate. Herein, we report tomographic X-ray absorption spectroscopy measurements that reveal the presence dissimilar iron specific localization within...
Ni contamination from crude oil in the fluid catalytic cracking (FCC) process is one of primary sources catalyst deactivation, thereby promoting dehydrogenation-hydrogenation and speeding up coke growth. Herein, single-particle X-ray fluorescence, diffraction absorption (μXRF-μXRD-μXAS) tomography used combination with confocal fluorescence microscopy (CFM) after thiophene staining to spatially resolve interaction components study zeolite degradation, including processes dealumination...
Abstract The acquisition of photosynthesis is a fundamental step in the evolution eukaryotes. However, few phototrophic organisms are unambiguously recognized Precambrian record. situ detection metabolic byproducts individual microfossils key for direct identification their metabolisms. Here, we report new integrative methodology using synchrotron-based X-ray fluorescence and absorption. We evidence bound nickel-geoporphyrins moieties low-grade metamorphic rocks, preserved within cells ~1...
Micro- and nanoscopic X-ray techniques were used to investigate the relationship between uranium (U) tissue distributions adverse effects digestive tract of aquatic model organism
Highlights•Correlative ptychographic tomography with 35 nm resolution and diffraction tomography•3D micro-cracks in secondary Li-rich NMC particles correlated crystal lattice•Radial secondary-particle-size-dependent material degradation•Intriguing core-shell structure observed 3D crystalline mapsSummaryThe search for higher performance, improved safety, lifetime of lithium-ion batteries relies on the understanding degradation mechanisms. Complementary to methods studies primary or bulk...
Slag-containing pastes and concretes were analysed by element-specific synchrotron-based techniques to determine the speciation of iron on crushed materials through spatially resolved micro-spectroscopic studies. The investigated cement samples hydrated either in laboratory, or exposed river sea water. Metallic iron, along with minor proportions sulphide magnetite was detected laboratory sample. Iron sulphide, goethite, siliceous hydrogarnet discovered blended slag cements contact water for...
We developed a spectro-nanotomography method that enables fast chemical characterization of functional materials.
Abstract The introduction of structural defects in metal–organic frameworks (MOFs), often achieved through the fractional use defective linkers, is emerging as a means to refine properties existing MOFs. These missing coordination fragments, create unsaturated framework nodes that may alter MOF. A property‐targeted utilization this approach demands an understanding structure defect‐engineered We demonstrate full‐field X‐ray absorption near‐edge computed tomography can help improve our...
Powder bed density, flowability, and laser light absorption of the powder strongly influence quality performance aluminum oxide parts processed by selective sintering melting. By means spray drying, highly dense granules with a good flowability are manufactured. An ultrasonic atomizer co‐current droplet air mixing used to aqueous slurries consisting either bimodal or trimodal distributions oxide. Nano‐iron improves interaction green pulsed laser. The improved is verified an Ulbricht sphere....
During laser-powder bed fusion (l-PBF) the printed material is subjected to multiple fast heating and cooling cycles when laser interacts with neighboring tracks or layers above. The complex thermal history influences final microstructure macroscopic properties of part. In this work, we demonstrate how high-speed in situ X-ray diffraction transmission mode can be used measure temperature profiles rates a Ti-6Al-4V single-track wall. remelting top layer, exceeding β transus (Tβ ∼ 1252 K)...
The study of liquid metal embrittlement in Fe–Zn systems is challenging because the high temperature and vapor pressure Zn, which hinders in-situ investigations with sufficiently spatial resolution. This typically associated subsecond processing steps coexistence a solid substrate Zn phase, renders direct observations at microstructural scale difficult. In this study, we comprehensively investigate reactions occurring during rapid heating cooling stages using synchrotron X-ray diffraction....
We report the characterization and applications of core–shell Cu–Ir nanocatalysts for oxygen reduction reaction evolution reaction. Core–shell particles with tunable thickness Ir can be oxidized to remove Cu core obtain shells. The shells determines stability optimization precious metals. showed in situ scanning transmission electron microscopy remarkable at elevated temperatures under oxidative reductive environments. In X-ray absorption spectroscopy also that traces remaining copper could...