Modelling the X-ray powder diffraction of nitrogen-expanded austenite using the Debye formula

2008 ◽  
Vol 41 (3) ◽  
pp. 537-543 ◽  
Author(s):  
Jette Oddershede ◽  
Thomas L. Christiansen ◽  
Kenny Ståhl
Keyword(s):  
Dislocation Density ◽  
Powder Diffraction ◽  
Stacking Faults ◽  
Screw Dislocations ◽  
X Ray ◽  
Debye Formula ◽  
Interstitial Nitrogen ◽  
Expanded Austenite

Stress-free and homogeneous samples of nitrogen-expanded austenite, a defect-rich f.c.c. structure with a high interstitial nitrogen occupancy (between 0.36 and 0.61), have been studied using X-ray powder diffraction and Debye simulations. The simulations confirm the presence of deformation stacking faults in the structure, while twin or growth faulting can be ruled out. Screw dislocations are abundant and the dislocation density increases with the interstitial nitrogen occupancy. Whether the N atoms are clustered or distributed randomly among the octahedral interstices was found to be indistinguishable to X-ray powder diffraction.

Classification of stacking faults and their stepwise elimination during the disorder → order transformation of nickel hydroxide

2006 ◽  
Vol 62 (4) ◽  
pp. 530-536 ◽  
Author(s):  
T. N. Ramesh ◽  
P. Vishnu Kamath ◽  
C. Shivakumara
Keyword(s):  
Diffraction Pattern ◽  
Powder Diffraction ◽  
Nickel Hydroxide ◽  
Stacking Faults ◽  
X Ray ◽  
Local Structures ◽  
Different Types ◽  
Different Temperatures ◽  
Stacking Patterns

Nickel hydroxide samples obtained by strong alkali precipitation are replete with stacking faults. The local structures of the stacking faults resemble the stacking patterns of different polytypic modifications that are theoretically possible among the layered hydroxides. This resemblance becomes a basis for the classification of stacking faults into different types. Each type of stacking fault produces a characteristic non-uniform broadening of peaks in the X-ray powder diffraction pattern of nickel hydroxide. DIFFaX simulations aid the classification and quantification of stacking faults. Hydrothermal treatment of a poorly ordered nickel hydroxide slurry at different temperatures (338–473 K) and different durations (5–48 h) shows that the stacking faults are removed in a stepwise manner. The as-precipitated sample has 17–20% stacking faults of the 3R 2 variety, which evolve into the 2H 2 type at 413 K. The 2H 2 stacking faults persist up to 443 K. The stacking faults are completely removed only at 473 K. At this temperature an ordered β-Ni(OH)2 phase is observed.

scholarly journals Studies of Crystal Imperfections in Ice with Reference to the Growth Process by the use of X-Ray Diffraction Topography and Divergent Laue Method

1978 ◽  
Vol 21 (85) ◽  
pp. 409-418 ◽  
Author(s):  
Yukiko Mizuno
Keyword(s):  
Dislocation Density ◽  
Growth Process ◽  
Stacking Faults ◽  
Great Majority ◽  
X Ray Diffraction ◽  
X Ray ◽  
Slow Growth Rate ◽  
Crystal Imperfections ◽  
Perfect Dislocation ◽  
Laue Method

AbstractThis paper presents studies on crystal imperfections including basal and non-basal dislocations, small-angle grain boundaries, stacking faults, and dislocation networks in ice using both X-ray diffraction and Laue techniques; these studies examined the growth process or origin of the ice, i.e. ice from glaciers, ice grown from the melt, or ice formed by sublimation. Several hoar crystals were found to be perfect, dislocation-free crystals, this may be due to their very slow growth rate. Dislocations and Shockley-type stacking faults were observed in some crystals. Dislocation density of a hoar crystal is very large at the point at which it started to grow, but away from this region the density becomes so small that no dislocation can be seen. The arrangement and structure of dislocations around vapour figures were also studied by means of X-ray diffraction topography. It was found that the dislocation density is high along the periphery of the vapour hexagon and that the great majority of dislocations within the hexagon are running from its centre towards the vertices or sides of the hexagon. Long screw dislocations with Burgers vector c <0001> were observed in a tabular ice which was formed artificially at a very slight degree of supercooling. The behaviour of dislocations in ice subjected to a tensile stress was studied by the use of the divergent X-ray technique which gives both enlarged Laue spots and a transmission pattern in the same photograph.

Crystal structure of metolazone, C16H16ClN3O3S

2019 ◽  
Vol 34 (4) ◽  
pp. 361-367 ◽  
Author(s):  
James A. Kaduk ◽  
Amy M. Gindhart ◽  
Thomas N. Blanton
Keyword(s):  
Crystal Structure ◽  
Hydrogen Bond ◽  
Powder Diffraction ◽  
Density Functional ◽  
Stacking Faults ◽  
Powder Diffraction Data ◽  
Hydrogen Bond Donor ◽  
Powder Diffraction File ◽  
X Ray ◽  
Ring Nitrogen

The crystal structure of metolazone has been solved and refined using synchrotron X-ray powder diffraction data and optimized using density functional techniques. Metolazone crystallizes in space group P-1 (#2) with a = 8.1976(5), b = 14.4615(69), c = 16.0993(86) Å, α = 115.009(18), β = 90.096(7), γ = 106.264(4)°, V = 1644.52(9) Å3, and Z = 4. The broad (02-1) peak at 3.42° 2θ indicates stacking faults along this direction. The crystal structure consists of alternating polar and hydrocarbon layers parallel to the ac-plane. Only one of the sulfonamide groups acts as a hydrogen bond donor. Both ring nitrogen atoms act as hydrogen bond donors, but one forms an N–H···N hydrogen bond, while the other participates in an N–H···O bond. The powder pattern has been submitted to ICDD® for inclusion in the Powder Diffraction File™, to replace entry 00-066-1624.

Interaction of 6H-Type Stacking Faults with Threading Screw Dislocations in PVT-Grown 4H-SiC Single Crystals

2012 ◽  
Vol 717-720 ◽  
pp. 411-414
Author(s):  
Shinya Sato ◽  
T. Fujimoto ◽  
H. Tsuge ◽  
M. Katsuno ◽  
W. Ohashi
Keyword(s):  
High Resolution ◽  
Single Crystals ◽  
Room Temperature ◽  
Stacking Faults ◽  
Screw Dislocations ◽  
X Ray

6H-type stacking faults (SFs) observed in PVT-grown 4H-SiC ingle crystals were investigated using Photoluminescence (PL) microscopy at room temperature. Structural analyses using high resolution X-ray topography have revealed that there exist no (n=4, 8) component in Burger’s vectors of the 6H-type SFs we observed, strongly suggesting that the 6H-type SFs are constructed either by insertions of very thin 6H-type foreign polytype inclusions or by successive repetitions of Shockley-type in-plane glides.

Influence of planar defects on powder diffractograms of fcc metals

2002 ◽  
Vol 17 (4) ◽  
pp. 270-277 ◽  
Author(s):  
A. I. Ustinov ◽  
N. M. Budarina
Keyword(s):  
Powder Diffraction ◽  
Stacking Faults ◽  
Diffraction Peak ◽  
High Concentration ◽  
Planar Defects ◽  
X Ray ◽  
Fcc Metals ◽  
Different Types ◽  
High Degree ◽  
Kinematic Approach

X-ray powder diffractograms from fcc crystals containing high concentration (more than 1%) of planar defects [deformation stacking faults (SF), double deformation SF, twin boundaries (TB)] have been simulated by Monte Carlo method in kinematic approach. It was shown that the characteristics of powder diffraction peak profiles (except peaks with indexes H00) dependent nonmonotonically on PD concentration, during which peak maximums stay in Bragg positions. An addition point to emphasize is that an appearance of TB only in the crystal not affects on position of all peaks. Several types of PD to be occurred simultaneously in the crystal influence on powder diffractograms additively. Peculiarities of the powder diffraction pattern inherent in different types of PD have been revealed to permit predominant PD type to be found with a high degree of accuracy based on experimental data.

VOPO4·H2O: A Stacking Faults Structure Studied by X-ray Powder Diffraction and DFT-D Calculations

2011 ◽  
Vol 50 (10) ◽  
pp. 4378-4383 ◽  
Author(s):  
Romain Gautier ◽  
Nathalie Audebrand ◽  
Eric Furet ◽  
Régis Gautier ◽  
Eric Le Fur
Keyword(s):  
Powder Diffraction ◽  
Stacking Faults ◽  
X Ray

Structural Transformation from TSDs to Frank-Type Stacking Faults by Giant Bunched Steps in PVT-Grown 4H-SiC Single Crystals

2016 ◽  
Vol 858 ◽  
pp. 97-100 ◽  
Author(s):  
Shinya Sato ◽  
Tatsuo Fujimoto ◽  
Hiroshi Tsuge ◽  
Masakazu Katsuno ◽  
Masashi Nakabayashi ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Single Crystals ◽  
Structural Transformation ◽  
Stacking Faults ◽  
Stacking Sequence ◽  
Screw Dislocations ◽  
X Ray ◽  
Transmission Electron ◽  
High Resolution Tem ◽  
Stacking Structure

Structural transformation from threading screw dislocations (TSDs) to stacking faults (SFs) has been investigated for PVT-grown 4H-SiC single crystals using X-ray topography and transmission electron microscopy (TEM). The transformation of TSDs is induced by the structural interference with bunched surface macrosteps over 100 nm in height. The stacking sequence of a SF was determined to be (433) in Zadanov's notation by using high-resolution TEM. Our detailed analyses revealed that the (433) stacking structure can be constructed by a combination of five faults including both four Frank type faults and one Shockley type fault.

Order and disorder in NMC layered materials: a FAULTS simulation analysis

2017 ◽  
Vol 32 (S1) ◽  
pp. S213-S220 ◽  
Author(s):  
Marine Reynaud ◽  
Montse Casas-Cabanas
Keyword(s):  
Powder Diffraction ◽  
Simulation Analysis ◽  
Structural Information ◽  
Stacking Faults ◽  
Structural Models ◽  
Layered Materials ◽  
Neutron Powder Diffraction ◽  
X Ray ◽  
Order And Disorder ◽  
Different Types

The program FAULTS has been used to simulate the X-ray powder diffraction (XRD), neutron powder diffraction (NPD), and electron diffraction (ED) patterns of several structural models for LiNi1/3Mn1/3Co1/3O2, including different types of ordering of the transition metal (TM) cations in the TM slabs, different amounts of Li+/NiII+ cation mixing and different amounts of stacking faults. The results demonstrate the relevance of the structural information provided by NPD and ED data as compared with XRD to characterize the microstructure of NMC (LiNi1−y-zMnyCozO2) compounds.

Determination of the type of stacking faults in single-crystal high-purity diamond with a low dislocation density of <50 cm−2by synchrotron X-ray topography

2016 ◽  
Vol 55 (4) ◽  
pp. 040303 ◽  
Author(s):  
Satoshi Masuya ◽  
Kenji Hanada ◽  
Takumi Uematsu ◽  
Tomoya Moribayashi ◽  
Hitoshi Sumiya ◽  
...  
Keyword(s):  
Dislocation Density ◽  
Single Crystal ◽  
High Purity ◽  
Stacking Faults ◽  
X Ray ◽  
Low Dislocation Density

The influence of the structure of molybdenum disulphide on its reactivity

1987 ◽  
Vol 52 (3) ◽  
pp. 678-685 ◽  
Author(s):  
Lidmila Bartovská ◽  
Čestmír Černý
Keyword(s):  
Gibbs Energy ◽  
Excellent Agreement ◽  
Powder Diffraction ◽  
Energy Equation ◽  
Solid Phase ◽  
Stacking Faults ◽  
Gaseous Mixture ◽  
Crystalline Form ◽  
Molybdenum Disulphide ◽  
X Ray

The equilibrium in the system Mo-MoS2-H2S-H2 was studied between 569.4 and 1 276.8 K. The equilibrium gaseous mixture was analyzed by an iodometric method, the solid phase was studied by X-ray powder diffraction. The structure of MoS2 changed in the course of measurements from a “poorly crystalline” form at lower temperatures to a “well crystalline” one with a small number of stacking faults at higher temperatures. The poorly crystalline form is more reactive than the well crystalline one. For the formation of the well crystalline form of MoS2 a Gibbs-energy equation, ΔG0 (J mol-1) = -390 100 + 176.7T, was derived. It is in excellent agreement with the equation derived from the data obtained by fluorine calorimetry.

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