Nucleation and Growth of Triangular Prismatic Iron Carbides in Amorphous Films by In Situ Transmission Electron Microscopy

2011 ◽  
Vol 172-174 ◽  
pp. 959-964 ◽  
Author(s):  
Elizabeth Bauer-Grosse
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Carbon Content ◽  
Carbon Film ◽  
Nucleation And Growth ◽  
Orientation Relationships ◽  
Iron Carbides ◽  
Transmission Electron ◽  
Nucleation Sites

The crystallization mechanisms of sputtered Fe1-xCx amorphous thin films for three values of atomic carbon content x = 0.28, 0.30 and 0.32 are directly observed using hot stage transmission electron microscopy. Images recorded sequentially are used to track the change caused by heating. Observations concern the nucleation and the growth of iron carbides and their structural identification. Information is also given about their crystallochemistry. They belong to the family of interstitial carbides with carbon atoms located inside iron Triangular Prisms (TP). They are built either from TP Sheets (TPS) stacks deriving from the cementite θ-Fe3C or from TP Chains (TPC) arrangements deriving from the Eckström-Adcock Fe7C3 carbide. The sharp transition between dominant TPS and dominant TPC carbides formations is illustrated. Nucleation and growth processes of both types of carbides are discussed and focus is put on the TPC crystals. They are the first to be formed whatever carbon content of the specimen and really correspond to the dominant phase for the richest-carbon film. When they are less numerous, they can act as nucleation sites for TPS carbides and it is in situ illustrated during the crystallization of the poorest-carbon film where orientation relationships can be found between the TPC-Fe7C3 carbideand a TPS carbide close to the Hägg carbide χ-Fe5C2 The crystallization ofFe0.70C0.30 film corresponds to a particular case where TPC carbides and TPS carbides can coexist with the same composition.

Nucleation Dynamics of Water Nanodroplets

2014 ◽  
Vol 20 (2) ◽  
pp. 407-415 ◽  
Author(s):  
Dipanjan Bhattacharya ◽  
Michel Bosman ◽  
Venkata R.S.S. Mokkapati ◽  
Fong Yew Leong ◽  
Utkur Mirsaidov
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Gold Nanoparticles ◽  
Heterogeneous Nucleation ◽  
Flat Surface ◽  
Nucleation And Growth ◽  
Length Scale ◽  
Transmission Electron ◽  
Nucleation Sites

AbstractThe origin of the condensation of water begins at the nanoscale, a length-scale that is challenging to probe for liquids. In this work we directly image heterogeneous nucleation of water nanodroplets by in situ transmission electron microscopy. Using gold nanoparticles bound to a flat surface as heterogeneous nucleation sites, we observe nucleation and growth of water nanodroplets. The growth of nanodroplet radii follows the power law: R(t)~(t−t0)β, where β~0.2−0.3.

Reactions in Metal-Metalloid Multilayers

1993 ◽  
Vol 311 ◽  
Author(s):  
Robert Sinclair ◽  
Toyohiko J. Konno
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Differential Scanning Calorimetry ◽  
Reactive Systems ◽  
Nucleation And Growth ◽  
In Situ Observation ◽  
Scanning Calorimetry ◽  
Compound Formation ◽  
Transmission Electron

ABSTRACTWe have studied the reactions at metal-metalloid interfaces using high resolution transmission electron microscopy, including in situ observation, and differential scanning calorimetry. There is contrasting behavior depending on the affinity for interaction or segregation. For reactive systems, compound formation ultimately results, but this can be preceded by solidstate amorphization. For non-reactive systems, crystallization of the metalloid is often achieved with nucleation and growth mediated by the metal phase.

Visualization of regulated nucleation and growth of lithium sulfides for high energy lithium sulfur batteries

2019 ◽  
Vol 12 (10) ◽  
pp. 3144-3155 ◽  
Author(s):  
Zheng-Long Xu ◽  
Sung Joo Kim ◽  
Donghee Chang ◽  
Kyu-Young Park ◽  
Kyun Seong Dae ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
High Energy ◽  
Nucleation And Growth ◽  
Transmission Electron ◽  
Lithium Sulfur Batteries ◽  
Lithium Sulfur

The nucleation and growth of lithium sulfides are directly observed by liquid in situ transmission electron microscopy.

In situ silicification of an Icelandic hot spring microbial mat: implications for microfossil formation

1995 ◽  
Vol 32 (12) ◽  
pp. 2021-2026 ◽  
Author(s):  
S. Schultze-Lam ◽  
F. G. Ferris ◽  
K. O. Konhauser ◽  
R. G. Wiese
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Hot Spring ◽  
Microbial Mat ◽  
Chloroflexus Aurantiacus ◽  
X Ray ◽  
Exceptional Preservation ◽  
Transmission Electron ◽  
Nucleation Sites

Transmission electron microscopy and energy-dispersive x-ray analysis revealed that filamentous phototrophic bacteria resembling Chloroflexus aurantiacus underwent rapid silicification in an Icelandic hot spring microbial mat. The mineralization associated with the cells occurred both extracellularly, within and on the external sheaths of the bacteria, and intracellularly, within the cytoplasm. The exceptional preservation of the bacterial sheaths is due to the presence of distinct mineral nucleation sites. This results in the production of silica casts of the bacteria, which bear a striking resemblance to microbial remains in ancient microfossil assemblages.

Initial Oxidation Kinetics of Cu(100), (110), and (111) Thin Films Investigated by in Situ Ultra-high-vacuum Transmission Electron Microscopy

2005 ◽  
Vol 20 (7) ◽  
pp. 1684-1694 ◽  
Author(s):  
Guangwen Zhou ◽  
Judith C. Yang
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Surface Diffusion ◽  
High Vacuum ◽  
Nucleation And Growth ◽  
Ultra High Vacuum ◽  
Initial Oxidation ◽  
Transmission Electron ◽  
Oxygen Surface

The initial oxidation stages of Cu(100), (110), and (111) surfaces have been investigated by using in situ ultra-high-vacuum transmission electron microscopy (TEM) techniques to visualize the nucleation and growth of oxide islands. The kinetic data on the nucleation and growth of oxide islands shows a highly enhanced initial oxidation rate on the Cu(110) surface as compared with Cu(100), and it is found that the dominant mechanism for the nucleation and growth is oxygen surface diffusion in the oxidation of Cu(100) and (110). The oxidation of Cu(111) shows a dramatically different behavior from that of the other two orientations, and the in situ TEM observation reveals that the initial stages of Cu(111) oxidation are dominated by the nucleation of oxide islands at temperatures lower than 550 °C, and are dominated by two-dimensional oxide growth at temperatures higher than 550 °C. This dependence of the oxidation behavior on the crystal orientation and temperature is attributed to the structures of the oxygen-chemisorbed layer, oxygen surface diffusion, surface energy, and the interfacial strain energy.

Nucleation Phenomena during Titanium Silicon Reaction

1989 ◽  
Vol 146 ◽  
Author(s):  
Ivo J.M.M. Raaijmakers ◽  
Leo J. van Ijzendoorn ◽  
Anton M.L. Theunissen ◽  
Ki-Bum Kim
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
High Resolution ◽  
Cross Section ◽  
Nucleation And Growth ◽  
Diffusion Control ◽  
Transmission Electron ◽  
First Results ◽  
Titanium Silicon

ABSTRACTIt is known that thermal annealing of Ti and amorphous (α) Si first results in an amorphous silicide, after which the crystalline disilicide grows under diffusion control. The situation with respect to the reaction of Ti with crystalline (x) Si is much less clear. We have investigated the reaction of Ti with xSi with (high resolution) cross-section transmission electron microscopy and in-situ Rutherford backscattering spectroscopy. It is shown that an amorphous silicide can also be formed on crystalline Si. The presence of this amorphous silicide as a precursor to the C49TiSi2 phase is suggested to be an important issue in the nucleation and growth of the disilicide.

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