Nucleation and growth of gas bubbles in AlSi8Mg4 foam investigated by X-ray tomoscopy

2020 ◽  
pp. 116583
Author(s):  
Paul Hans Kamm ◽  
Tillmann Robert Neu ◽  
Francisco García-Moreno ◽  
John Banhart
Keyword(s):  
Gas Bubbles ◽  
Nucleation And Growth ◽  
X Ray

Detonation Synthesis of Nano-Size Materials

1995 ◽  
Vol 418 ◽  
Author(s):  
J. Forbes ◽  
J. Davis ◽  
C. Wong
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Nucleation And Growth ◽  
Detonation Synthesis ◽  
X Ray Diffraction ◽  
Crystalline Materials ◽  
X Ray ◽  
Transmission Electron ◽  
Nano Size

AbstractThe detonation of explosives typically creates 100's of kbar pressures and 1000's K temperatures. These pressures and temperatures last for only a fraction of a microsecond as the products expand. Nucleation and growth of crystalline materials can occur under these conditions. Recovery of these materials is difficult but can occur in some circumstances. This paper describes the detonation synthesis facility, recovery of nano-size diamond, and plans to synthesize other nano-size materials by modifying the chemical composition of explosive compounds. The characterization of nano-size diamonds by transmission electron microscopy and electron diffraction, X-ray diffraction and Raman spectroscopy will also be reported.

Direct in situ observation of ZnO nucleation and growth via transmission X-ray microscopy

Nanoscale ◽  
2016 ◽  
Vol 8 (4) ◽  
pp. 1849-1853 ◽  
Author(s):  
S. E. R. Tay ◽  
A. E. Goode ◽  
J. Nelson Weker ◽  
A. A. Cruickshank ◽  
S. Heutz ◽  
...  
Keyword(s):  
Functional Properties ◽  
Nucleation And Growth ◽  
In Situ Observation ◽  
X Ray ◽  
Size And Morphology

The nucleation and growth of a nanostructure controls its size and morphology, and ultimately its functional properties.

scholarly journals In situ X-ray Diffraction Investigation of the Crystallisation of Perfluorinated Ce(IV)-based Metal-Organic Frameworks with UiO-66 and MIL-140 architectures

2020 ◽  
Author(s):  
Stephen Shearan ◽  
Jannick Jacobsen ◽  
Ferdinando Costantino ◽  
Roberto D’Amato ◽  
Dmitri Novikov ◽  
...  
Keyword(s):  
Crystal Growth ◽  
Metal Organic Frameworks ◽  
Building Blocks ◽  
Nucleation And Growth ◽  
X Ray Diffraction ◽  
X Ray ◽  
Rate Determining Step ◽  
Wide Range ◽  
Metal Organic

We report on the results of a thorough <i>in situ</i> synchrotron powder X-ray diffraction study of the crystallisation in aqueous medium of two recently discovered perfluorinated Ce(IV)-based metal-organic frameworks (MOFs), analogues of the already well investigated Zr(IV)-based UiO-66 and MIL-140A, namely, F4_UiO-66(Ce) and F4_MIL-140A(Ce). The two MOFs were originally obtained in pure form in similar conditions, using ammonium cerium nitrate and tetrafluoroterephthalic acid as building blocks, and small variations of the reaction parameters were found to yield mixed phases. Here, we investigate the crystallisation of these compounds <i>in situ</i> in a wide range of conditions, varying parameters such as temperature, amount of the protonation modulator nitric acid (HNO<sub>3</sub>) and amount of the coordination modulator acetic acid (AcOH). When only HNO<sub>3</sub> is present in the reaction environment, F4_MIL-140A(Ce) is obtained as a pure phase. Heating preferentially accelerates nucleation, which becomes rate determining below 57 °C, whereas the modulator influences nucleation and crystal growth to a similar extent. Upon addition of AcOH to the system, alongside HNO<sub>3</sub>, mixed-phased products, consisting of F4_MIL-140A(Ce) and F4_UiO-66(Ce), are obtained. In these conditions, F4_UiO-66(Ce) is always formed faster and no interconversion between the two phases occurs. In the case of F4_UiO-66(Ce), crystal growth is always the rate determining step. An increase in the amount of HNO<sub>3</sub> slows down both nucleation and growth rates for F4_MIL-140A(Ce), whereas nucleation is mainly affected for F4_UiO-66(Ce). In addition, a higher amount HNO<sub>3</sub> favours the formation of F4_MIL-140A(Ce). Similarly, increasing the amount of AcOH leads to slowing down of the nucleation and growth rate, but favours the formation of F4_UiO-66(Ce). The pure F4_UiO-66(Ce) phase could also be obtained when using larger amounts of AcOH in the presence of minimal HNO<sub>3</sub>. Based on these <i>in situ</i> results, a new optimised route to achieving a pure, high quality F4_MIL-140A(Ce) phase in mild conditions (60 °C, 1 h) is also identified.

Nucleation and Growth of Carbon Dioxide Gas Bubbles

2005 ◽  
pp. 365-375 ◽  
Author(s):  
Anne M. Hilton ◽  
Michael J. Hey ◽  
Rodney D. Bee
Keyword(s):  
Carbon Dioxide ◽  
Gas Bubbles ◽  
Nucleation And Growth ◽  
Carbon Dioxide Gas

scholarly journals Revisiting Models for Spheroidal Graphite Growth

2018 ◽  
Vol 925 ◽  
pp. 118-124 ◽  
Author(s):  
Mathias Karsten Bjerre ◽  
Mohammed Azeem ◽  
Peter D. Lee ◽  
Jesper Henri Hattel ◽  
Niels Skat Tiedje
Keyword(s):  
Growth Rate ◽  
Cast Iron ◽  
Numerical Model ◽  
Final Stage ◽  
Nucleation And Growth ◽  
Ductile Cast Iron ◽  
Spheroidal Graphite ◽  
Microstructure Formation ◽  
X Ray ◽  
Graphite Growth

Recent experiments resolved nucleation and growth of graphite during solidification of ductile cast iron in 4D using synchrotron X-ray tomography. A numerical model for microstructure formation during solidification is compared with the experiments. Despite very good overall agreement between observations of spheroidal graphite growth and model results, significant deviations exist towards the end of solidification. We use the experimental observations to analyse the relation between graphite growth rate and the state of the particle neighbourhood to pinpoint possible links between growth rate of individual graphite spheres and the overall solidification state. With this insight we revisit existing models for growth of spheroidal graphite and discuss possible modifications in order to correctly describe the critical final stage of solidification.

scholarly journals Zn Electrodeposition on Single-Crystal GaN(0001) Surface: Nucleation and Growth Mechanism

2016 ◽  
Vol 2016 ◽  
pp. 1-8 ◽  
Author(s):  
Fei Peng ◽  
Shuang-Jiao Qin ◽  
Yu Zhao ◽  
Ge-Bo Pan
Keyword(s):  
Single Crystal ◽  
Electrochemical Techniques ◽  
Deposition Process ◽  
Nucleation And Growth ◽  
X Ray Diffraction ◽  
X Ray ◽  
Surface Nucleation ◽  
Instantaneous Nucleation ◽  
Nucleation And Growth Mechanism ◽  
Transient Measurements

The electrochemical deposition of zinc on single-crystaln-type GaN(0001) from a sulphate solution has been investigated on the basis of electrochemical techniques including cyclic voltammetry, chronoamperometry, and Tafel plot. The morphology and crystal structure of zinc deposits have been characterized by means of scanning electron microscopy, X-ray diffraction, and energy-dispersive X-ray analysis. The result has revealed that the deposition of Zn on GaN electrode commenced at a potential of −1.12 V versus Ag/AgCl. According to the Tafel plot, an exchange current density of ~0.132 mA cm−2was calculated. In addition, the current transient measurements have shown that Zn deposition process followed the instantaneous nucleation in 10 mM ZnSO4+ 0.5 M Na2SO4+ 0.5 M H3BO3(pH = 4).

Effect of Manganese on Titanium Thin Films Adhesion Deposited on Steel Substrates

2012 ◽  
Vol 326-328 ◽  
pp. 583-586
Author(s):  
R. Gheriani ◽  
Raouf Mechiakh
Keyword(s):  
Thin Films ◽  
Annealing Temperature ◽  
Vacuum Annealing ◽  
Pure Titanium ◽  
Nucleation And Growth ◽  
Thin Solid Films ◽  
X Ray ◽  
Solid Films ◽  
Titanium Thin Films ◽  
Steel Substrates

The mainly property of thin solid films technologies is their adhesion to the substrates. Because of its good wear resistance and its low coefficient of friction against steel, TiC is an attractive coating material for wear applications such as bearing components. The adhesion of TiC coatings, however suffers from insufficient reproducibility, which is probably due to uncontrolled process parameters. In our work pure titanium thin films of approximately 0.6 µm in thickness were prepared on 100C6 stainless steel substrates by cathodic sputtering. The samples were subjected to secondary vacuum annealing at a temperature between 400 and 1000°C for 30 min. The reaction between substrates and thin films was characterized using an x-ray diffractometer (XRD). Surface morphology and elements diffusion evaluations were carried out by scanning electron microscope (SEM) and energy dispersive spectroscopy (EDS). The interaction substrates-thin films is accompanied by nucleation and growth of titanium carbide as a function of annealing temperature. By the SEM and EDS results, it appears clearly that the diffusion of manganese to the external layers leads to the destruction of adhesion especially at high temperatures.

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