An X-ray investigation of the thermal decomposition of portlandite

1969 ◽  
Vol 37 (286) ◽  
pp. 244-249 ◽  
Author(s):  
N. H. Brett
Keyword(s):  
Thermal Decomposition ◽  
Electron Diffraction ◽  
Single Crystals ◽  
Nucleation Rate ◽  
Surface Defects ◽  
X Rays ◽  
X Ray ◽  
Mechanism Of Decomposition ◽  
Homogeneous Mechanism

SummaryThe thermal decomposition of portlandite, Ca(OH)2, has been studied in air and in vacuum using X-ray single-crystal techniques. In air, the crystals were decomposed in situ on the goniometer arcs whilst X-ray reflections were simultaneously recorded. The transformation to CaO was not accompanied by topotaxy; this is attributed to the high nucleation rate of CaO crystallites in air. When Ca(OH)2 single crystals were decomposed under vacuum (and subsequently exposed to X-rays), some orientation of the CaO crystallites occurred. These results are compared with those of previous workers using electron-diffraction techniques. Decomposition of Ca(OH)2 single crystals commences at ∼ 450 °C in air and at ∼ 230 °C in a vacuum of 10−6 mmHg; reaction commences at crystal edges and surface defects, the reaction boundary moving inwards to the centre of the crystal. This observation is consistent with a homogeneous mechanism of decomposition.

Recrystallization of AA1050 Studied by 3DXRD

2006 ◽  
Vol 519-521 ◽  
pp. 1569-1578
Author(s):  
Dorte Juul Jensen
Keyword(s):  
Single Crystals ◽  
High Energy ◽  
Nucleation And Growth ◽  
X Rays ◽  
X Ray Diffraction ◽  
Orientation Relationships ◽  
X Ray ◽  
3 Dimensional ◽  
Kinetics Of

By 3 dimensional X-ray diffraction (3DXRD) using high energy X-rays from synchrotron sources it is possible to study in-situ the nucleation and growth during recrystallization. In this paper it is described and discussed how 3DXRD can supplement EBSP measurements of nucleation and growth. Three types of studies are considered: i) orientation relationships between nuclei and parent deformed matrix, ii) recrystallization kinetics of individual bulk grains and iii) filming of growing grains in deformed single crystals.

Evolution of Pore Ordering during Anodizing of Aluminum Single Crystals: In Situ Small-Angle X-ray Scattering Study

2021 ◽  
Author(s):  
Ilya V. Roslyakov ◽  
Andrei P. Chumakov ◽  
Andrei A. Eliseev ◽  
Alexey P. Leontiev ◽  
Oleg V. Konovalov ◽  
...  
Keyword(s):  
Single Crystals ◽  
Small Angle ◽  
X Ray ◽  
X Ray Scattering ◽  
Scattering Study ◽  
Ray Scattering

In Situ Testing and X Rays Radiation Effects of Pt/Bi3.15Nd0.85Ti3O12/Pt Ferroelectric Capacitors

2013 ◽  
Vol 712-715 ◽  
pp. 293-297
Author(s):  
Li Li
Keyword(s):  
Radiation Effects ◽  
Hysteresis Loops ◽  
Electrical Performance ◽  
Hysteresis Curve ◽  
X Rays ◽  
Shanghai Synchrotron Radiation Facility ◽  
X Ray ◽  
In The Beginning ◽  
Ferroelectric Capacitors

Pt/Bi3.15Nd0.85Ti3O12(BNT)/Pt ferroelectric capacitors were monitored using in situ X-ray irradiation with 10 keV at BL14B1 beamline (Shanghai Synchrotron Radiation Facility). BL14B1 combined with a ferroelectric analyzer enabled measurements in situ of electrical performance. The hysteresis curve (PE) of distortion depended on the polarization during irradiation, but the diffracted intensities of the (117) peak did not change in the beginning. ThePEcurve had a negligible change from 2.09×109Gy to 4.45×109Gy. Finally, bothPrandPr+very rapidly increased, but the intensities of (117) decreased. The hysteresis loops were remarkably deformed at the maximum total dose of 4.87×109Gy.

Applications of High-Resolution Powder X-Ray Diffraction

2007 ◽  
Vol 130 ◽  
pp. 7-14 ◽  
Author(s):  
Andrew N. Fitch
Keyword(s):  
High Resolution ◽  
Synchrotron Radiation ◽  
Powder Diffraction ◽  
X Rays ◽  
X Ray Diffraction ◽  
Crystalline Materials ◽  
X Ray ◽  
Structural Characterisation ◽  
Pdf Analysis

The highly-collimated, intense X-rays produced by a synchrotron radiation source can be harnessed to build high-resolution powder diffraction instruments with a wide variety of applications. The general advantages of using synchrotron radiation for powder diffraction are discussed and illustrated with reference to the structural characterisation of crystalline materials, atomic PDF analysis, in-situ and high-throughput studies where the structure is evolving between successive scans, and the measurement of residual strain in engineering components.

On the dimorphism of Pr6Mo10O39

2017 ◽  
Vol 72 (11) ◽  
pp. 765-774
Author(s):  
Daniel Rudolph ◽  
Sonja Laufer ◽  
Ingo Hartenbach
Keyword(s):  
Crystal Structure ◽  
Thermal Decomposition ◽  
Single Crystals ◽  
Main Product ◽  
Molar Ratio ◽  
Coordination Environment ◽  
Space Group ◽  
Coordination Numbers ◽  
Dense Modification

AbstractAttempts to synthesize Pr4Mo7O27 using Pr, Pr6O11 and MoO3 in a molar ratio of 8:6:77 led to a main product of scheelite-type Pr0.667[MoO4] and few single crystals of the triclinic A-type Pr6Mo10O39. The latter crystallizes in space group P1̅ (a=945.25(1), b=1058.49(2), c=1815.16(3) pm; α=104.149(1), β=95.220(1), γ=102.617(1)°, Z=2). Its crystal structure comprises six crystallographically independent Pr3+ cations, eight tetrahedral [MoO4]2− units, and one [Mo2O7]2− entity. The cations display coordination numbers of seven (1×) and eight (5×), while the [MoO4]2− tetrahedra are surrounded by five Pr3+ cations each. The [Mo2O7]2− anions exhibit a coordination environment of seven Pr3+ cations. The attempt to synthesize PrF[MoO4] using PrOF (from in situ thermal decomposition of PrF[CO3]) as reagent did not lead to the desired product but to monoclinic B-type Pr6Mo10O39. This slightly less dense modification compared to its triclinic analogue crystallizes in space group C2/c (a=1247.93(3), b=1989.68(6), c=1392.52 (4) pm, β=100.505(2)°, Z=4) with three crystallographically independent Pr3+ cations, four [MoO4]2− tetrahedra, and again one [Mo2O7]2− unit in the crystal structure. Thus, both Pr6Mo10O39 modifications are better described with the structured formula Pr6[MoO4]8[Mo2O7]. The coordination numbers around the Pr3+ cations are seven (1×) and eight (2×) while all four [MoO4]2− anions are again surrounded by five Pr3+ cations each. Six of the latter represent the coordination environment around the [Mo2O7]2− entities. Besides the thorough comparison of the crystal structures single crystal Raman spectra were recorded for both Pr6Mo10O39 phases.

Diffraction

2012 ◽  
Vol 20 (2) ◽  
pp. 7-7
Author(s):  
Charles Lyman
Keyword(s):  
Electron Diffraction ◽  
100Th Anniversary ◽  
Primary Phase ◽  
Phase Identification ◽  
X Rays ◽  
X Ray Diffraction ◽  
Identification Methods ◽  
X Ray ◽  
Structure Of Matter

This year marks the 100th anniversary of the discovery of X-ray diffraction and the 85th anniversary of electron diffraction (see Microscopy Pioneers). For most of the time since their introduction, microscopists have known these two techniques as the primary phase identification methods used in conjunction with various microscopies. However, these two diffraction methods also have played enormous roles in understanding the structure of matter, as well as the nature of both X rays and electrons.

scholarly journals In situ damage assessment using synchrotron X-rays in materials loaded by a Hopkinson bar

2014 ◽  
Vol 372 (2015) ◽  
pp. 20130191 ◽  
Author(s):  
Weinong W. Chen ◽  
Matthew C. Hudspeth ◽  
Ben Claus ◽  
Niranjan D. Parab ◽  
John T. Black ◽  
...  
Keyword(s):  
High Speed ◽  
Particle Interaction ◽  
Tensile Failure ◽  
High Rate ◽  
X Rays ◽  
Contrast Imaging ◽  
X Ray ◽  
Damage Initiation ◽  
Dynamic Experiments

Split Hopkinson or Kolsky bars are common high-rate characterization tools for dynamic mechanical behaviour of materials. Stress–strain responses averaged over specimen volume are obtained as a function of strain rate. Specimen deformation histories can be monitored by high-speed imaging on the surface. It has not been possible to track the damage initiation and evolution during the dynamic deformation inside specimens except for a few transparent materials. In this study, we integrated Hopkinson compression/tension bars with high-speed X-ray imaging capabilities. The damage history in a dynamically deforming specimen was monitored in situ using synchrotron radiation via X-ray phase contrast imaging. The effectiveness of the novel union between these two powerful techniques, which opens a new angle for data acquisition in dynamic experiments, is demonstrated by a series of dynamic experiments on a variety of material systems, including particle interaction in granular materials, glass impact cracking, single crystal silicon tensile failure and ligament–bone junction damage.

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