Crystallization kinetics of atomic crystals revealed by a single-shot and single-particle X-ray diffraction experiment

2021 ◽  
Vol 118 (51) ◽  
pp. e2111747118
Author(s):  
Akinobu Niozu ◽  
Yoshiaki Kumagai ◽  
Toshiyuki Nishiyama Hiraki ◽  
Hironobu Fukuzawa ◽  
Koji Motomura ◽  
...  
Keyword(s):  
Materials Science ◽  
Natural Phenomenon ◽  
Stable Phase ◽  
Single Shot ◽  
Face Centered Cubic ◽  
Diffraction Experiment ◽  
X Ray Diffraction ◽  
X Ray ◽  
Face Centered ◽  
Fcc Phase

Crystallization is a fundamental natural phenomenon and the ubiquitous physical process in materials science for the design of new materials. So far, experimental observations of the structural dynamics in crystallization have been mostly restricted to slow dynamics. We present here an exclusive way to explore the dynamics of crystallization in highly controlled conditions (i.e., in the absence of impurities acting as seeds of the crystallites) as it occurs in vacuum. We have measured the early formation stage of solid Xe nanoparticles nucleated in an expanding supercooled Xe jet by means of an X-ray diffraction experiment with 10-fs X-ray free-electron laser (XFEL) pulses. We found that the structure of Xe nanoparticles is not pure face-centered cubic (fcc), the expected stable phase, but a mixture of fcc and randomly stacked hexagonal close-packed (rhcp) structures. Furthermore, we identified the instantaneous coexistence of the comparably sized fcc and rhcp domains in single Xe nanoparticles. The observations are explained by the scenario of structural aging, in which the nanoparticles initially crystallize in the highly stacking-disordered rhcp phase and the structure later forms the stable fcc phase. The results are reminiscent of analogous observations in hard-sphere systems, indicating the universal role of the stacking-disordered phase in nucleation.

In situ high-temperature X-ray diffraction characterization of silver sulfide, Ag2S

2011 ◽  
Vol 26 (2) ◽  
pp. 114-118 ◽  
Author(s):  
Thomas Blanton ◽  
Scott Misture ◽  
Narasimharao Dontula ◽  
Swavek Zdzieszynski
Keyword(s):  
High Temperature ◽  
Structure Refinement ◽  
Silver Sulfide ◽  
Rietveld Analysis ◽  
Face Centered Cubic ◽  
X Ray Diffraction ◽  
X Ray ◽  
Face Centered ◽  
Fcc Phase

Silver sulfide, Ag2S, is most commonly known as the tarnish that forms on silver surfaces due to the exposure of silver to hydrogen sulfide. The mineral acanthite is a monoclinic crystalline form of Ag2S that is stable to 176°C. Upon heating above 176°C, there is a phase conversion to a body-centered cubic (bcc) form referred to as argentite. Further heating above 586°C results in conversion of the bcc phase to a face-centered cubic (fcc) phase polymorph. Both high-temperature cubic phases are solid-state silver ion conductors. In situ high-temperature X-ray diffraction was used to better understand the polymorphs of Ag2S on heating. The existing powder diffraction file (PDF) entries for the high-temperature fcc polymorph are of questionable reliability, prompting a full Rietveld structure refinement of the bcc and fcc polymorphs. Rietveld analysis was useful to show that the silver atoms are largely disordered and can only be described by unreasonably large isotropic displacement parameters or split site models.

Metallurgical Aspects of High-palladium Alloys

1988 ◽  
Vol 67 (10) ◽  
pp. 1307-1311 ◽  
Author(s):  
P.R. Mezger ◽  
A.L.H. Stols ◽  
M.M.A. Vrijhoef ◽  
E.H. Greener
Keyword(s):  
Face Centered Cubic ◽  
Body Centered Cubic ◽  
Palladium Alloys ◽  
Secondary Phases ◽  
X Ray Diffraction ◽  
X Ray ◽  
Simple Cubic ◽  
Face Centered ◽  
Fcc Phase ◽  
Multi Phase

Nine commercial high-Pd alloys were investigated. Microstructure and phase composition were screened by x-ray diffraction, light microscopy, and an electron microprobe. After being etched, some high-Pd alloys revealed dendritic structures. The others showed a more homogeneous structure with distinct grain boundaries. Etching was necessary to reveal distinct structures, though the overall etching effect turned out to be limited. On unetched specimens, only a slight chemical heterogeneity could be determined. Except for one alloy, the systems turned out to have complex multi-phase structures. The main face-centered-cubic (fcc) phase was Pd-based. As secondary phases, body-centered-cubic (bcc) and/or simple cubic ones were detected. The latter phases were similar to a Cu3Ga and PdGa intermetallic compound, respectively. Face-centered-tetragonal (fct) structures reported by other investigators were not found.

Stabilization of Thick Fcc Cobalt Layers by One Monolayer of Manganese in Co/Mn Superlattices

1998 ◽  
Vol 528 ◽  
Author(s):  
V. Pierron-Bohnes ◽  
A. Michel ◽  
J.P. Jay ◽  
P. Panissod
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Buffer Layer ◽  
Structural Properties ◽  
Face Centered Cubic ◽  
X Ray Diffraction ◽  
X Ray ◽  
The Face ◽  
Face Centered ◽  
Fcc Phase

AbstractEpitaxial Co/Mn superlattices (0.6 to 4.8 nm thick Co) have been grown on (0002) hcp Ru buffer layer on mica substrates. The face centered cubic (fcc) phase of cobalt is stabilized by the very thin manganese layer. The structural properties of these layers have been studied through x ray diffraction and nuclear magnetic resonance.

Stacking Faults in a High Nitrogen Face-Centered-Cubic Phase Formed on Nitrogen-Modified Austenitic Stainless Steel

2008 ◽  
Vol 373-374 ◽  
pp. 318-321
Author(s):  
J. Liang ◽  
M.K. Lei
Keyword(s):  
Stainless Steel ◽  
Plasma Source ◽  
Peak Shift ◽  
Cubic Phase ◽  
Face Centered Cubic ◽  
X Ray Diffraction ◽  
High Nitrogen ◽  
X Ray ◽  
Peak Asymmetry ◽  
Face Centered

Effects of stacking faults in a high nitrogen face-centered-cubic phase (γΝ) formed on plasma source ion nitrided 1Cr18Ni9Ti (18-8 type) austenitic stainless steel on peak shift and peak asymmetry of x-ray diffraction were investigated based on Warren’s theory and Wagner’s method, respectively. The peak shift from peak position of the γΝ phase is ascribed to the deformation faults density α, while the peak asymmetry of the γΝ phase is characterized by deviation of the center of gravity of a peak from the peak maximum (Δ C.G.) due to the twin faults density β. The calculated peak positions of x-ray diffraction patterns are consistent with that measured for plasma source ion nitrided 1Cr18Ni9Ti stainless steel.

Theoretical and experimental study of the gradient properties and the resulting local crystalline structure and orientation in magnetron-sputtered CrAlN coatings with lateral composition and thickness gradient

2017 ◽  
Vol 50 (4) ◽  
pp. 1000-1010
Author(s):  
Bärbel Krause ◽  
Michael Stüber ◽  
Anna Zimina ◽  
Ralph Steininger ◽  
Mareike Trappen ◽  
...  
Keyword(s):  
Target Surface ◽  
Sample Surface ◽  
Composition Gradient ◽  
Face Centered Cubic ◽  
X Ray Diffraction ◽  
X Ray ◽  
Al Content ◽  
Spatially Resolved ◽  
Composition Profiles ◽  
Face Centered

Cr–Al–N coatings with a lateral composition gradient were deposited from two segmented Cr/Al targets with different segment size, thus covering the Al content range 0.22 ≲ c ≲ 0.87 and a thickness range from several hundred nanometres to several micrometres. The two-dimensional thickness and composition profiles were determined nondestructively from X-ray fluorescence maps. The results were reproduced by simulations of the flux distribution on the sample surface, combiningTRIDYNsimulations of the reactive sputter process at the target surface andSIMTRAsimulations of the subsequent transport through the gas phase. The phase formation was studied by spatially resolved X-ray diffraction and X-ray absorption spectroscopy at the Cr Kedge. Forc ≲ 0.69, a single-phase solid solution face-centered cubic (f.c.c.) (Cr,Al)N phase was found, and for 0.69 ≲ c ≲ 0.87 coexisting f.c.c. (Cr,Al)N and hexagonal close packed (h.c.p.) (Cr,Al)N phases were observed. The biaxial texture formation in nearly the entire composition range indicates a zone T growth. Four, mainly composition-dependent, texture regions were identified. All observed textures are closely related to textures reported for the h.c.p. AlN and f.c.c. CrN parent phases. Forc ≳ 0.69, a strong thickness dependence of the textures was observed. The measurements reveal an orientation relation between different f.c.c. and h.c.p. textures, indicating that local epitaxy might play a role in the structure formation.

Structural, morphological, and magnetic study of nanocrystalline cobalt-copper powders synthesized by the polyol process

1995 ◽  
Vol 10 (6) ◽  
pp. 1546-1554 ◽  
Author(s):  
G.M. Chow ◽  
L.K. Kurihara ◽  
K.M. Kemner ◽  
P.E. Schoen ◽  
W.T. Elam ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Face Centered Cubic ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Copper Powders ◽  
Face Centered ◽  
Increasing Temperature ◽  
X Ray Absorption

Nanocrystalline CoxCu100−x (4 ⋚ x ⋚ 49 at. %) powders were prepared by the reduction of metal acetates in a polyol. The structure of powders was characterized by x-ray diffraction (XRD), transmission electron microscopy (TEM), high resolution transmission electron microscopy (HRTEM), extended x-ray absorption fine structure (EXAFS) spectroscopy, solid-state nuclear magnetic resonance (NMR) spectroscopy, and vibrating sample magnetometry (VSM). As-synthesized powders were composites consisting of nanoscale crystallites of face-centered cubic (fcc) Cu and metastable face-centered cubic (fcc) Co. Complementary results of XRD, HRTEM, EXAFS, NMR, and VSM confirmed that there was no metastable alloying between Co and Cu. The NMR data also revealed that there was some hexagonal-closed-packed (hcp) Co in the samples. The powders were agglomerated, and consisted of aggregates of nanoscale crystallites of Co and Cu. Upon annealing, the powders with low Co contents showed an increase in both saturation magnetization and coercivity with increasing temperature. The results suggested that during preparation the nucleation of Cu occurred first, and the Cu crystallites served as nuclei for the formation of Co.

Synthesis and Characterization of Cobalt-Nickel Nanowires Formed under External Magnetic Field

2015 ◽  
Vol 799-800 ◽  
pp. 120-124 ◽  
Author(s):  
Mary Donnabelle L. Balela ◽  
Lalaine M. Dulin ◽  
Erica A. Garcia ◽  
M. Janelle H. Tica
Keyword(s):  
Magnetic Field ◽  
External Magnetic Field ◽  
Face Centered Cubic ◽  
X Ray Diffraction ◽  
X Ray ◽  
Hexagonal Close Packed ◽  
Cobalt Nickel ◽  
Nickel Nanowires ◽  
Face Centered

Cobalt-nickel (Co-Ni) nanowires were formed by electroless deposition in ethylene glycol under external magnetic field. The effects of initial Co (II) and Ni (II) concentration on the surface and morphology of the synthesized nanowires were investigated by x-ray diffraction (XRD) and scanning electron microscope (SEM) respectively. An increase in the Co (II) concentration resulted in increase in diameter of the nanowires. However, the length of nanowires was observed to decrease. Higher Co (II) concentration resulted in a mixture of hexagonal close-packed and face-centered cubic Co-Ni nanowires. X-ray diffraction revealed that crystal growth occurred when the nanowires are annealed at 653 K for 10h.

Controlling Aspect Ratio of Copper Group Nanowire Arrays by Electrochemical Deposition in the Nanopores of AAO

2011 ◽  
Vol 335-336 ◽  
pp. 429-432 ◽  
Author(s):  
Xiu Yu Sun ◽  
Fa Qiang Xu
Keyword(s):  
Aspect Ratio ◽  
Nanowire Arrays ◽  
Face Centered Cubic ◽  
X Ray Diffraction ◽  
X Ray ◽  
Anodic Aluminum ◽  
Au Nanowire ◽  
The Face ◽  
Face Centered ◽  
Xrd Patterns

Highly ordered Cu, Ag and Au nanowire arrays with high aspect ratio and highly dense self-supporting nanowire patterns of copper group were successfully prepared using cyclic voltammetry with the assistance of anodic aluminum oxide (AAO) template. The X-ray diffraction (XRD) patterns of the metal nanowries were indexed to the face-centered cubic structure. The field emission scanning electron microscope (FE-SEM) results demonstrated that the length of nanowire could be controlled by changing the electrodepositon conditions. The aspect ratio of nanowire arrays can be tuned.

The Influence of Stacking Fault Energy on the Cold-Rolling Cu and Cu-Al Alloy: Structure and Mechanics Properties

2011 ◽  
Vol 683 ◽  
pp. 95-102 ◽  
Author(s):  
Hao Yang ◽  
Peng Yang ◽  
Jing Mei Tao ◽  
Cai Ju Li ◽  
Xin Kun Zhu
Keyword(s):  
Cold Rolling ◽  
Deformation Twin ◽  
High Strength ◽  
Liquid Nitrogen Temperature ◽  
Al Alloy ◽  
Face Centered Cubic ◽  
X Ray Diffraction ◽  
X Ray ◽  
Face Centered ◽  
Strength And Ductility

Sacking fault energy (SFE) is the key role in solving this problem of getting high strength and expected ductility simultaneously. This work adds Al as the procedure of decreasing SFE in Cu face-centered cubic. It is an economic and effective method to counterpart Cold-rolling at liquid nitrogen temperature to get high density deformation twin and ultrafine-grains size. After undergoing tensile and X-ray diffraction tests, Cu-4.5 wt.% Al plays the best performance on both strength and ductility. Thus there exist the optimal SFE of Cu-Al alloys which get both high strength and expected ductility simultaneously.

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