Thermally induced nucleation. I. A new way to obtain activation energies for unimolecular reactions

1983 ◽  
Vol 79 (6) ◽  
pp. 2763-2770 ◽  
Author(s):  
Joseph L. Katz ◽  
Joseph G. Ruggiero ◽  
Richard Partch ◽  
Dale Warren ◽  
F. H. Ebetino
Keyword(s):  
Activation Energies ◽  
Unimolecular Reactions ◽  
Thermally Induced

[(η5-C5Me5)Ru]+ fragments ligated to polyaromatic hydrocarbons: an experimental and computational approach to pathways for haptotropic migration

2015 ◽  
Vol 44 (1) ◽  
pp. 316-329 ◽  
Author(s):  
Matias Rioja ◽  
Paul Hamon ◽  
Thierry Roisnel ◽  
Sourisak Sinbandhit ◽  
Mauricio Fuentealba ◽  
...  
Keyword(s):  
Dft Calculations ◽  
Polyaromatic Hydrocarbons ◽  
Activation Energies ◽  
Computational Approach ◽  
High Activation ◽  
Thermally Induced

DFT calculations indicated rather high activation energies for the thermally induced intramolecular inter-ring haptotropic migration of the [(η5-C5Me5)Ru+] moiety.

Modeling The Evolution of Ellipsometric Data During The Thermally Induced Pt-Silicide Formation: Activation Energies and Prefactors

1999 ◽  
Vol 569 ◽  
Author(s):  
L. Ley ◽  
T. Stark ◽  
M. Hundhausen ◽  
H. Gruenleitner
Keyword(s):  
Accurate Determination ◽  
Reaction Model ◽  
Activation Energies ◽  
Optical Data ◽  
Heating Rates ◽  
Actual Distribution ◽  
Thermally Induced ◽  
Reaction Rate Constants ◽  
Reaction Fronts ◽  
Temperature Signal

ABSTRACTThe formation of Pt silicide (PtSi) by the thermally activated reaction of a 23 nm Pt layer on Si was monitored in situ by ellipsometry. Characteristic changes in the ellipsometric angles as a function of temperature signal the approach of two reaction fronts to the surface: one belonging to the Pt/Pt2Si and the other to the Pt2Si/PtSi interface. An analysis of the evolution of the ellipsometric angles as a function of temperature for different heating rates allows the accurate determination of the average activation energies of the two reactions. From a modeling of the optical data in terms of a specific reaction model further kinetic parameters such as the reaction rate constants and the actual distribution of activation energies have been deduced.

Nonisothermal Kinetics Study of Phase Evolution of Zn-Fe Intermetallics

1995 ◽  
Vol 398 ◽  
Author(s):  
O. N. C. Uwakweh ◽  
Z. T. Liu ◽  
M. Boisson
Keyword(s):  
Mechanical Alloying ◽  
Phase Evolution ◽  
Activation Energies ◽  
Intermetallic Phases ◽  
Kinetics Study ◽  
Nonisothermal Kinetics ◽  
Thermally Induced ◽  
Fe Intermetallics

ABSTRACTThrough mechanical alloying of pure elemental powders of Fe and Zn, true homogeneous alloys of Γ (Fe3Zn10), Γ1 (Fe5Zn21), δ (FeZn7) and ζ (FeZn13) intermetallic phases are formed. Based on nonisothermal kinetics analyses, the highest activation energies associated with the metastable to stable transformations of these phases are determined as follows: 170±1 kJ/mol, 2 51±2 kJ/mol, 176±1 kJ/mol and 73 7±4 kJ/mol for the Γ, Γ1, δ and ζ-phases, respectively. These values reflect different diffusion/thermally induced processes associated with the transition of each of these phases.

Morphologies of Nonadherent Al2O3 and Matching Substrate Surfaces

1972 ◽  
Vol 30 ◽  
pp. 524-525
Author(s):  
C. S. Giggins ◽  
J. K. Tien ◽  
B. H. Kear ◽  
F. S. Pettit
Keyword(s):  
Electron Microscopy ◽  
Oxide Scale ◽  
Oxidation Resistance ◽  
Substrate Surface ◽  
Morphological Features ◽  
Thermally Induced ◽  
Oxide Spallation ◽  
Oxidation Resistant ◽  
Induced Stresses ◽  
Substrate Surfaces

The performance of most oxidation resistant alloys and coatings is markedly improved if the oxide scale strongly adheres to the substrate surface. Consequently, in order to develop alloys and coatings with improved oxidation resistance, it has become necessary to determine the conditions that lead to spallation of oxides from the surfaces of alloys. In what follows, the morphological features of nonadherent Al2O3, and the substrate surfaces from which the Al2O3 has spalled, are presented and related to oxide spallation.The Al2O3, scales were developed by oxidizing Fe-25Cr-4Al (w/o) and Ni-rich Ni3 (Al,Ta) alloys in air at 1200°C. These scales spalled from their substrates upon cooling as a result of thermally induced stresses. The scales and the alloy substrate surfaces were then examined by scanning and replication electron microscopy.The Al2O3, scales from the Fe-Cr-Al contained filamentary protrusions at the oxide-gas interface, Fig. 1(a). In addition, nodules of oxide have been developed such that cavities were formed between the oxide and the substrate, Fig. 1(a).

Applications of ultramicrotomy for materials characterization

1993 ◽  
Vol 51 ◽  
pp. 232-233
Author(s):  
R.T. Blackham ◽  
J.J. Haugh ◽  
C.W. Hughes ◽  
M.G. Burke
Keyword(s):  
Materials Science ◽  
Microstructural Analysis ◽  
Analytical Electron Microscopy ◽  
Austenitic Stainless Steels ◽  
Specimen Preparation ◽  
Preparation Technique ◽  
Thermally Induced ◽  
Radiation Induced ◽  
Characterization Of Materials

Essential to the characterization of materials using analytical electron microscopy (AEM) techniques is the specimen itself. Without suitable samples, detailed microstructural analysis is not possible. Ultramicrotomy, or diamond knife sectioning, is a well-known mechanical specimen preparation technique which has been gaining attention in the materials science area. Malis and co-workers and Glanvill have demonstrated the usefulness and applicability of this technique to the study of a wide variety of materials including Al alloys, composites, and semiconductors. Ultramicrotomed specimens have uniform thickness with relatively large electron-transparent areas which are suitable for AEM anaysis.Interface Analysis in Type 316 Austenitic Stainless Steel: STEM-EDS microanalysis of grain boundaries in austenitic stainless steels provides important information concerning the development of Cr-depleted zones which accompany M23C6 precipitation, and documentation of radiation induced segregation (RIS). Conventional methods of TEM sample preparation are suitable for the evaluation of thermally induced segregation, but neutron irradiated samples present a variety of problems in both the preparation and in the AEM analysis, in addition to the handling hazard.

Spin-crossover in an iron(iii) complex showing a broad thermal hysteresis

2021 ◽  
Author(s):  
Cyril Rajnák ◽  
Romana Mičová ◽  
Ján Moncoľ ◽  
Ľubor Dlháň ◽  
Christoph Krüger ◽  
...  
Keyword(s):  
Schiff Base ◽  
Schiff Base Ligand ◽  
Spin Crossover ◽  
Thermal Hysteresis ◽  
Mononuclear Complex ◽  
Hysteresis Width ◽  
Thermally Induced

A pentadentate Schiff-base ligand 3,5Cl-L2− and NCSe− form a iron(iii) mononuclear complex [Fe(3,5Cl-L)(NCSe)], which shows a thermally induced spin crossover with a broad hysteresis width of 24 K between 123 K (warming) and 99 K (cooling).

Thermally induced budding of phospholipid vesicles — a discontinuous process

1993 ◽  
Vol 3 (5) ◽  
pp. 631-645 ◽  
Author(s):  
J. Käs ◽  
E. Sackmann ◽  
R. Podgornik ◽  
S. Svetina ◽  
B. Žekš
Keyword(s):  
Phospholipid Vesicles ◽  
Thermally Induced ◽  
Discontinuous Process
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