scholarly journals X-ray fluorescence induced by standing waves in the grazing-incidence and grazing-exit modes: study of the Mg–Co–Zr system

2015 ◽  
Vol 22 (6) ◽  
pp. 1419-1425 ◽  
Author(s):  
Yuchun Tu ◽  
Yanyan Yuan ◽  
Karine Le Guen ◽  
Jean-Michel André ◽  
Jingtao Zhu ◽  
...  
Keyword(s):  
Standing Waves ◽  
Chemical Characterization ◽  
Grazing Incidence ◽  
Free Energies ◽  
X Ray ◽  
Buried Interfaces ◽  
Opposite Behavior ◽  
The Difference ◽  
Mixing Enthalpies

The characterization of Mg–Co–Zr tri-layer stacks using X-ray fluorescence induced by X-ray standing waves, in both the grazing-incidence (GI) and the grazing-exit (GE) modes, is presented. The introduction of a slit in the direction of the detector improves the angular resolution by a factor of two and significantly improves the sensitivity of the technique for the chemical characterization of the buried interfaces. By observing the intensity variations of the MgKα and CoLα characteristic emissions as a function of the incident (GI mode) or detection (GE mode) angle, it is shown that the interfaces of the Si/[Mg/Co/Zr]×30multilayer are abrupt, whereas in the Si/[Mg/Zr/Co]×30multilayer a strong intermixing occurs at the Co-on-Zr interfaces. An explanation of this opposite behavior of the Co-on-Zr and Zr-on-Co interfaces is given by the calculation of the mixing enthalpies of the Co–Mg, Co–Zr and Mg–Zr systems, which shows that the Co–Zr system presents a negative value and the other two systems present positive values. Together with the difference of the surface free energies of Zr and Co, this leads to the Mg/Zr/Co system being considered as a Mg/CoxZrybi-layer stack, withx/yestimated around 3.5.

X-RAY DIFFRACTION FOR SURFACES AND BURIED INTERFACES

2000 ◽  
Vol 07 (04) ◽  
pp. 437-446 ◽  
Author(s):  
G. RENAUD
Keyword(s):  
Grazing Incidence ◽  
X Rays ◽  
X Ray Diffraction ◽  
X Ray ◽  
Grain Sizes ◽  
Buried Interfaces ◽  
Surfaces And Interfaces ◽  
Coherent Interfaces

The application of X-rays to the structural characterization of surfaces and interfaces, in situ and in UHV, is discussed on selected examples. Grazing incidence X-ray diffraction is not only a very powerful technique for quantitatively investigating the atomic structure of surfaces and interfaces, but is also very useful for providing information on the interfacial registry for coherent interfaces or on the strain deformation, island and grain sizes for incoherent epilayers.

A refraction correction for buried interfaces applied to in situ grazing-incidence X-ray diffraction studies on Pd electrodes

2021 ◽  
Vol 28 (3) ◽  
Author(s):  
Alan T. Landers ◽  
David M. Koshy ◽  
Soo Hong Lee ◽  
Walter S. Drisdell ◽  
Ryan C. Davis ◽  
...  
Keyword(s):  
Critical Angle ◽  
Optical Constants ◽  
Grazing Incidence ◽  
X Ray Diffraction ◽  
Material Interface ◽  
Near Surface ◽  
X Ray ◽  
Buried Interfaces

In situ characterization of electrochemical systems can provide deep insights into the structure of electrodes under applied potential. Grazing-incidence X-ray diffraction (GIXRD) is a particularly valuable tool owing to its ability to characterize the near-surface structure of electrodes through a layer of electrolyte, which is of paramount importance in surface-mediated processes such as catalysis and adsorption. Corrections for the refraction that occurs as an X-ray passes through an interface have been derived for a vacuum–material interface. In this work, a more general form of the refraction correction was developed which can be applied to buried interfaces, including liquid–solid interfaces. The correction is largest at incidence angles near the critical angle for the interface and decreases at angles larger and smaller than the critical angle. Effective optical constants are also introduced which can be used to calculate the critical angle for total external reflection at the interface. This correction is applied to GIXRD measurements of an aqueous electrolyte–Pd interface, demonstrating that the correction allows for the comparison of GIXRD measurements at multiple incidence angles. This work improves quantitative analysis of d-spacing values from GIXRD measurements of liquid–solid systems, facilitating the connection between electrochemical behavior and structure under in situ conditions.

scholarly journals New Insights into the Crystal Chemistry of Elpidite, Na2Zr[Si6O15]·3H2O and (Na1+YCax□1−X−Y)Σ=2Zr[Si6O15]·(3−X)H2O, and Ab Initio Modeling of IR Spectra

Materials ◽  
2021 ◽  
Vol 14 (9) ◽  
pp. 2160
Author(s):  
Alexander Bogdanov ◽  
Ekaterina Kaneva ◽  
Roman Shendrik
Keyword(s):  
Ir Spectra ◽  
Structural Models ◽  
Chemical Characterization ◽  
Chemical Compositions ◽  
X Ray Diffraction ◽  
Special Group ◽  
X Ray ◽  
Influence Of Water ◽  
Radioactive Species

Elpidite belongs to a special group of microporous zirconosilicates, which are of great interest due to their capability to uptake various molecules and ions, e.g., some radioactive species, in their structural voids. The results of a combined electron probe microanalysis and single-crystal X-ray diffraction study of the crystals of elpidite from Burpala (Russia) and Khan-Bogdo (Mongolia) deposits are reported. Some differences in the chemical compositions are observed and substitution at several structural positions within the structure of the compounds are noted. Based on the obtained results, a detailed crystal–chemical characterization of the elpidites under study was carried out. Three different structure models of elpidite were simulated: Na2ZrSi6O15·3H2O (related to the structure of Russian elpidite), partly Ca-replaced Na1.5Ca0.25ZrSi6O15·2.75H2O (close to elpidite from Mongolia), and a hypothetical CaZrSi6O15·2H2O. The vibration spectra of the models were obtained and compared with the experimental one, taken from the literature. The strong influence of water molecule vibrations on the shape of IR spectra of studied structural models of elpidite is discussed in the paper.

scholarly journals Nanotechnology in Roman Opaque Red Glass from the 2nd Century AD. Archaeometric Investigation in Red Sectilia from the Decoration of the Lucius Verus Villa in Rome

Heritage ◽  
2019 ◽  
Vol 2 (3) ◽  
pp. 2597-2611 ◽  
Author(s):  
Mario Bandiera ◽  
Patrice Lehuédé ◽  
Marco Verità ◽  
Luis Alves ◽  
Isabelle Biron ◽  
...  
Keyword(s):  
Chemical Composition ◽  
Chemical Characterization ◽  
Second Step ◽  
Colorimetric Analysis ◽  
Historical Sources ◽  
Pixe Analysis ◽  
X Ray ◽  
Colorimetric Measurements ◽  
Shed Light

This work aims to characterise the chemical composition of Roman opaque red glass sectilia dated to the 2nd century A.D and to shed light on Roman glassmaking production of different shades of red, from red to reddish-brown. Due to the lack of technical historical sources for this period many questions about technological aspects still remain. In this project a multi-disciplinary approach is in progress to investigate the red glass sectilia with several red hues from the Imperial Villa of Lucius Verus (161–169 A.D.) in Rome. First, colorimetric measurements were taken to identify the various red hues. The second step was chemical characterization of the samples and the identification of crystalline colouring phases. Particle Induced X-Ray Emission (PIXE) analysis was used to investigate the chemical composition of these glass samples, while the crystalline phases were identified by Raman Spectroscopy and Scanning Electrons Microscope with Energy Dispersive X-ray Spectrometry (SEM-EDS). Using SEM-EDS nanoparticles were detected as a colouring agent, the chemical composition and the morphology of which has been studied in depth. This information has been compared with the colorimetric analysis to establish any correlation with the different colour hues.

Reference-free, depth-dependent characterization of nanolayers and gradient systems with advanced grazing incidence X-ray fluorescence analysis

2015 ◽  
Vol 212 (3) ◽  
pp. 523-528 ◽  
Author(s):  
Philipp Hönicke ◽  
Blanka Detlefs ◽  
Matthias Müller ◽  
Erik Darlatt ◽  
Emmanuel Nolot ◽  
...  
Keyword(s):  
Fluorescence Analysis ◽  
Grazing Incidence ◽  
X Ray ◽  
Gradient Systems

Characterization of amorphous-Si/1ML-Ge/Si(001) Interface Structure by X-ray Standing Waves

2003 ◽  
Vol 42 (Part 1, No. 11) ◽  
pp. 7050-7052 ◽  
Author(s):  
Shinichiro Nakatani ◽  
Kazushi Sumitani ◽  
Akinobu Nojima ◽  
Toshio Takahashi ◽  
Keiichi Hirano ◽  
...  
Keyword(s):  
Standing Waves ◽  
Interface Structure ◽  
X Ray ◽  
Amorphous Si

Influence of the Residue of Casting by Lost Wax in the Modulus of Elasticity and Porosity of Concretes

2014 ◽  
Vol 805 ◽  
pp. 343-349
Author(s):  
Carine F. Machado ◽  
Weber G. Moravia
Keyword(s):  
Construction Industry ◽  
Modulus Of Elasticity ◽  
Chemical Characterization ◽  
Microstructural Characterization ◽  
Cement Matrix ◽  
X Ray Diffraction ◽  
X Ray ◽  
Hardened State ◽  
Material Powder

This work evaluated the influence of additions of the ceramic shell residue (CSR), from the industries of Lost Wax Casting, in the modulus of elasticity and porosity of concrete. The CSR was ground and underwent a physical, chemical, and microstructural characterization. It was also analyzed, the environmental risk of the residue. In the physical characterization of the residue were analyzed, the surface area, and particle size distribution. In chemical characterization, the material powder was subjected to testing of X-ray fluorescence (XRF). Microstructural characterization was performed by scanning electron microscopy (SEM) and X-ray diffraction (XRD). The residue was utilized like addition by substitution of cement in concrete in the percentages of 10% and 15% by weight of Portland cement. It was evaluated properties of concrete in the fresh and hardened state, such as compressive strength, modulus of elasticity, absorption of water by total immersion and by capillarity. The results showed that the residue can be used in cement matrix and improve some properties of concrete. Thus, the CSR may contribute to improved sustainability and benefit the construction industry.

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