Hydrogen Behavior in NdRh3-Based Hydrides

2016 ◽  
Vol 369 ◽  
pp. 163-167
Author(s):  
Stepan Alexandrovich Lushnikov ◽  
Tatyana Victorovna Filippova
Keyword(s):  
Diffraction Method ◽  
Hydrogen Desorption ◽  
X Ray Diffraction ◽  
Hydrogen Atoms ◽  
X Ray ◽  
Cubic Lattice ◽  
Cubic Lattices ◽  
Rate Of Heating ◽  
The Difference ◽  
Two Phases

Samples of desorbed NdRh3-based hydrides have been investigated by the X-ray diffraction method. X-ray data analysis showed that the samples contain two phases with hexagonal and cubic lattices. It was revealed that proportion of these phases in the samples depends on the rate of heating before the hydrogen desorption. At high rates of the heating in the desorbed samples amount of the phase with cubic lattice increased. This behaviour of the hydrogen in hydrides can be explained by the difference in the diffusion of disordered and ordered hydrogen atoms.

Stability of MgH2 Samples after Thermodesorption

2017 ◽  
Vol 371 ◽  
pp. 14-17
Author(s):  
Stepan Alexandrovich Lushnikov ◽  
Tatyana Victorovna Filippova
Keyword(s):  
Liquid Nitrogen ◽  
Diffraction Method ◽  
Ambient Condition ◽  
Hydride Phase ◽  
X Ray Diffraction ◽  
Hydrogen Atoms ◽  
X Ray ◽  
Two Phases ◽  
Fast Quenching

Samples of partly desorbed MgH2 have been studied by the X-ray diffraction method. All samples contained two phases (Mg and MgH2) and were stable at ambient condition for several months. After fast quenching in liquid nitrogen the samples became unstable and transformed after several days into Mg. The rate of decomposition depends on the amount ratio of Mg and MgH2 phases in the sample. Destabilization of the hydride phase observed in quenched samples can be explained on the basis of different diffusion of disordered and ordered hydrogen atoms.

scholarly journals Electrochemical hydrogenation, lithiation and sodiation of the GdFe2–xMx and GdMn2–xMx intermetallics

2021 ◽  
pp. 139-149
Keyword(s):  
Electrode Materials ◽  
Electrochemical Impedance ◽  
Diffraction Method ◽  
Electrochemical Characteristics ◽  
Electrochemical Hydrogenation ◽  
Hydrogen Atoms ◽  
X Ray ◽  
Cell Parameters ◽  
The Difference ◽  
Better Than

Electrochemical hydrogenation, lithiation and sodiation of the phases GdFe2–xMx and GdMn2–xMx (M=Mn, Co, Ni, Zn, and Mg) and the influence of doping components on electrochemical characteristics of electrode materials on their basis were studied using X-ray powder diffraction method, scanning electron microscopy, energy dispersive X-ray analysis, X-ray fluorescent spectroscopy, cyclic voltammetry and electrochemical impedance spectroscopy. Phase analysis showed a simple correspondence between unit cell parameters of the phases and atomic radii of doping elements. Electrode materials based on GdFe2 and GdMn2 doped with 2 at.% of Co, Ni and Mg demonstrated better hydrogen sorption properties than those doped with Mn and Zn. Corrosion resistance of the doped electrodes was also better than of the binary analogues (e.g. corrosion potential of the GdFe2-based electrode was –0.162 V whereas that of GdFe1.96Ni0.04 was –0.695 V). The capacity parameters were increased in the following ranges: Zn<Mn<Mg<Co<Ni and Zn<Fe<Mg<Co<Ni for GdFe2–xMx and GdMn2–xMx, respectively. After fifty cycles of charge/discharge, we observed the changes in surface morphology and composition of the electrode samples. In the structure of studied Laves type phases with MgCu2-type structure, the most suitable sites for hydrogen atoms are tetrahedral voids 8a. During lithiation and sodiation of the phases, the atoms of the M-component of the structure are replaced by the atoms of lithium, and the atoms of gadolinium are replaced by the atoms of sodium. This difference in interaction is due to the difference in atomic sizes of the atoms. No insertion of lithium or sodium into the structural voids of the phases was observed.

In-Situ X-ray Diffraction Study of Lithium Intercalation in Nanostructured Anatase Titanium dioxide

1998 ◽  
Vol 536 ◽  
Author(s):  
R. Van de Krol ◽  
E. A. Meulenkamp ◽  
A. Goossens ◽  
J. Schoonman
Keyword(s):  
Phase Transformation ◽  
Maximum Amount ◽  
Lithium Intercalation ◽  
X Ray Diffraction ◽  
X Ray ◽  
Before And After ◽  
The Difference ◽  
Two Phases ◽  
Reversible Phase

AbstractElectrochemical lithium intercalation in nanostructured anatase TiO2 is investigated with in-situ X-ray diffraction. A complete and reversible phase transformation from tetragonal anatase TiO2 to orthorhombic anatase Li0.5TiO2 is observed. The difference of the XRD spectra before and after insertion can be fitted with the lattice parameters of the two phases as fit parameters. The maximum amount of lithium that can be dissolved in anatase TiO2 before the phase transformation occurs is found to be very small.

Review of Residual Stress Determination and Exploitation Techniques Using X-Ray Diffraction Method

2006 ◽  
Vol 524-525 ◽  
pp. 229-234
Author(s):  
M. Belassel ◽  
J. Pineault ◽  
M.E. Brauss
Keyword(s):  
Residual Stress ◽  
Diffraction Method ◽  
Point Of View ◽  
Stress And Strain ◽  
Stress Determination ◽  
Calculation Methods ◽  
X Ray Diffraction ◽  
X Ray ◽  
True Meaning ◽  
The Difference

Although x-ray diffraction techniques have been applied to the measurement of residual stress in the industry for decades, some of the related details are still unclear to many production and mechanical testing engineers working in the field. This is because these details, specifically those associated with the transition between diffraction and mechanics, are not always emphasized in the literature. This paper will emphasize the appropriate calculation methods and the steps necessary to perform high quality residual stress measurements. Additionally, details are given regarding the difference between mechanical and x-ray elastic constants, as well as the true meaning of stress and strain from both diffraction and strain gage point of view. Cases where the material is subject to loading above the yield limit are also included.

Estimation of The Critical Radius for The Nucleation of the C54 Phase in C49 TiSi2: Role of The Difference in Density

1999 ◽  
Vol 580 ◽  
Author(s):  
D.B. Migas ◽  
M. Iannuzzi ◽  
Leo Miglio ◽  
F. La Via ◽  
M.G. Grimaldi
Keyword(s):  
Ab Initio ◽  
Elastic Strain ◽  
Critical Radius ◽  
Lattice Parameters ◽  
X Ray Diffraction ◽  
X Ray ◽  
The Difference ◽  
Two Phases ◽  
The One

AbstractWe discuss the rather scattered measurements of the lattice parameters for C49 TiSi2, which are reported in literature, along with new and accurate X-ray diffraction measurements and ab-initio calculations. Both agree in indicating that the density of the metastable C49 structure cannot be much smaller than the one for the polymorphic C54 phase, as it is commonly reported. We conclude by demonstrating that only in the case of such a smaller difference in density between the two phases, the elastic strain contribution to the nucleation energy of the C54 structure in the C49 matrix can be neglected. The estimation of the critical radius strongly depends on this issue.

Retained Austenite Amount Determination Comparison in JIS SKD11 Steel Using Quantitative Metallography and X-Ray Diffraction Methods

2012 ◽  
Vol 482-484 ◽  
pp. 1165-1168 ◽  
Author(s):  
Yang Yu Su ◽  
Liu Ho Chiu ◽  
Tao Liang Chuang ◽  
Chien Lung Huang ◽  
Cheng Yen Wu ◽  
...  
Keyword(s):  
Diffraction Analysis ◽  
Tool Steel ◽  
Retained Austenite ◽  
Diffraction Method ◽  
Primary Carbide ◽  
Quantitative Metallography ◽  
X Ray Diffraction ◽  
X Ray ◽  
The Difference ◽  
Carbide Content

This research compares the difference in determining the austenite amount in SKD 11 tool steel using the micrographic method as opposed to the X-ray diffraction method. Calculating the amount of retained austenite in tool steel using X-ray diffraction analysis requires first taking off the primary carbide content. By etching the SKD11 specimen using Beraha’s CdS reagent, the retained austenite, martensite and carbide are shown as white, red and blue regions in the microstructure, respectively. With quantitative metallography, the retained austenite can be distinguished as separate micro-constituents and properly counted. However, the calculated values are lower than those acquired from the X-ray diffraction. It is more accurate to evaluate the amount of retained austenite with carbide by X-ray diffraction analysis.

scholarly journals Roentgenographic investigation of solid-phase equilibria in the PbSe-AgSbSe2system

2019 ◽  
Vol 2 (2) ◽  
Author(s):  
Babanly Mahammad Baba ◽  
Mansimova Shabnam Hamlet ◽  
OrujluElnur Najaf
Keyword(s):  
Phase Equilibria ◽  
Solid Solutions ◽  
Solid Phase ◽  
Diffraction Method ◽  
Lattice Parameters ◽  
X Ray Diffraction ◽  
X Ray ◽  
Cubic Lattice

The solid-phase equilibria in the 2PbSe-AgSbSe2system were studied by using the powder X-ray diffraction method.  It is established that the system is characterized by the formation of ~60 mol% solid solutions basedon AgSbSe2.Solubility based on PbSe is about 3mol%. The cubic lattice parameters of solid solutions are defined.

The crystal structure of potassium ΛΔ-rac-2,3-butanediamine-N,N,N',N'-tetraacetatecobaltate hemihydrate

1985 ◽  
Vol 50 (1) ◽  
pp. 171-187 ◽  
Author(s):  
Marián Kalina ◽  
Viktor Kettmann ◽  
František Pavelčík ◽  
Jaroslav Majer
Keyword(s):  
Crystal Structure ◽  
Equatorial Plane ◽  
Least Squares Method ◽  
Chelate Ring ◽  
Diffraction Method ◽  
Methyl Groups ◽  
X Ray Diffraction ◽  
Hydrogen Atoms ◽  
X Ray ◽  
Energy Preference

The crystal structure of ΛΔ-K [Co(rac-bdta)] . 1/2 H2O was solved by the X-ray diffraction method and refined by the least squares method to R = 0.047 on the basis of 3 847 diffraction values. The substance crystallizes in a space group with symmetry P 1 with the following lattice parameters: a = 0.9412(5), b = 1.2166(6), c = l.5370(9)nm, α = 70.68(4), β = 73.45(4), γ = 83.24(4)°. The crystal structure consists of two symmetrically independent enantiomer pairs Δ-[Co(R,R)-bdta] and Λ-[Co(S,S)-bdta]- K+ ions and molecules of water of crystallization. The Co(III) atom is octahedrally coordinated by rac(bdta)4- forming four glycine and one ethylenediamine chelate ring. The stereospecific coordination of rac(bdta)4- is based on an energy preference for equatorially located methyl groups on the central ethylenediamine ring. Two types of strain in the [Co(rac-bdta)]- complex are derived from the three five-membered rings in the equatorial plane of the complex and repulsion between the methyl and methylene hydrogen atoms.

The Stability of CeNi3-Based Intermetallic Hydrides

2015 ◽  
Vol 365 ◽  
pp. 24-29
Author(s):  
Stepan Alexandrovich Lushnikov ◽  
Tatyana Victorovna Filippova
Keyword(s):  
Phase Composition ◽  
Low Temperatures ◽  
Room Temperature ◽  
Diffraction Method ◽  
X Ray Diffraction ◽  
Hydrogen Atoms ◽  
X Ray ◽  
The Stability ◽  
Diffusion Of Hydrogen ◽  
Hydride Phases

Hydrides of CeNi3 intermetallic compounds were synthesized with hydrogen at a pressure of up to 50 bars at room and low temperatures. Using the X-ray diffraction method gives phase composition and lattice parameters of the hydride samples. It was revealed that one set of the hydride samples was stable in air and at room temperature, while another set was very unstable at the same conditions and rapidly desorbed hydrogen. This diverse behaviour depends on the proportion of obtained hydride phases at low and room temperatures, coexisting in the samples. A possible explanation has been proposed based on the different diffusion of hydrogen atoms in ordered and disordered hydride phases, incorporated in the samples.

Antiphase Boundaries in Ordered Ni3FE Crystals

1969 ◽  
Vol 27 ◽  
pp. 62-63
Author(s):  
Y. H. Liu
Keyword(s):  
Domain Size ◽  
Antiphase Domain ◽  
X Ray Diffraction ◽  
X Ray ◽  
Hardening Mechanism ◽  
Superlattice Structure ◽  
Disordered Phase ◽  
Domain Boundaries ◽  
Atomic Scattering ◽  
The Difference

Ordered Ni3Fe crystals possess a LI2 type superlattice similar to the Cu3Au structure. The difference in slip behavior of the superlattice as compared with that of a disordered phase has been well established. Cottrell first postulated that the increase in resistance for slip in the superlattice structure is attributed to the presence of antiphase domain boundaries. Following Cottrell's domain hardening mechanism, numerous workers have proposed other refined models also involving the presence of domain boundaries. Using the anomalous X-ray diffraction technique, Davies and Stoloff have shown that the hardness of the Ni3Fe superlattice varies with the domain size. So far, no direct observation of antiphase domain boundaries in Ni3Fe has been reported. Because the atomic scattering factors of the elements in NijFe are so close, the superlattice reflections are not easily detected. Furthermore, the domain configurations in NioFe are thought to be independent of the crystallographic orientations.

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