The role of non-bonding electron pairs in intermetallic compounds

2003 ◽  
Vol 32 (2) ◽  
pp. 80-86 ◽  
Author(s):  
Thomas F. Fässler
Keyword(s):  
Intermetallic Compounds ◽  
Electron Pairs ◽  
Bonding Electron

The role of non-bonding electron pairs in the asymmetric coordination environments of 1,1-dithiolate complexes

1976 ◽  
Vol 29 (11) ◽  
pp. 2541 ◽  
Author(s):  
BF Hoskins ◽  
CD Pannan
Keyword(s):  
Electron Pair ◽  
Central Atom ◽  
Main Group ◽  
Valence Shell ◽  
Electron Pairs ◽  
Shell Electron ◽  
Dithiolate Complexes ◽  
Asymmetric Coordination ◽  
Bonding Electron

Various forms of asymmetry in the lengths of the bond between the central atom and sulphur, found in differing coordination environments of 1,1-dithiolate compounds involving main group atoms, have been successfully rationalized by considering both the valence shell electron pair repulsion theory and the effect of the restricted ligand bite distance.

The Role of Ti Inoculation of Al-Zn-Si Coating Alloys on the Formation of Intermetallic Compounds by Interaction with Solid Steel

2007 ◽  
Vol 560 ◽  
pp. 97-102 ◽  
Author(s):  
Felipe García ◽  
Armando Salinas-Rodríguez ◽  
Enrique Nava-Vázquez
Keyword(s):  
Intermetallic Compounds ◽  
Liquid Alloy ◽  
Interfacial Layer ◽  
Intermetallic Layer ◽  
Coated Steel ◽  
Acid Dissolution ◽  
Steel Strips ◽  
Si Content ◽  
Interfacial Intermetallic Compounds

The reaction between solid steel and liquid Al-Zn-Si alloy leads to the formation of a solid intermetallic interfacial layer. In the case of industrial Al-43.5Zn-1.5Si coated steel strips, the thickness of the intermetallic layer is on average 1.35 μm and the kinetics of the reaction is controlled by the effect of Si on Al and Fe diffusivities through the solid intermetallic layer. In this paper it is shown that the thickness of the intermetallic interfacial layer decreases as the Si content in the liquid alloy increases. EDXS microanalysis at the interface of industrial coated steel strips shows that the interfacial intermetallic compounds are chemically similar to those formed in the bulk of Al-43.5Zn-1.5Si liquid baths in continuous coating lines. Differential acid dissolution of the coatings reveals that the intermetallic layer is not planar at the interface with the coating overlay and is formed by grains of different size and chemical composition. Addition of minute quantities of Ti to the Al-Zn-Si liquid alloy causes changes in the morphology of the intermetallic layer and an overall refining of the microstructure.

Mechanisms of ductility improvement in L12 compounds

1988 ◽  
Vol 3 (3) ◽  
pp. 426-440 ◽  
Author(s):  
Osamu Izumi ◽  
Takayuki Takasugi
Keyword(s):  
Grain Boundary ◽  
Grain Boundaries ◽  
Intermetallic Compounds ◽  
Present Article ◽  
Electronic Structures ◽  
Alloying Effect ◽  
Test Environment ◽  
Materials Development

The present article first describes some characteristics of structure, chemistry, and electronic (bond) nature for grain boundaries in the A3B Li2-type intermetallic compounds. Next, the phenomenological aspects for the grain boundary brittleness of the Li2-type intermetallic compounds are reviewed with respect to the combination of the constituent atoms, the alloying effect, the stoichiometry effect, and a role of impurity or gaseous atoms. It is emphasized that the brittleness of grain boundaries in the intermetallic compounds is directly controlled by the atomistic and electronic structures at grain boundary regions. Based on these systematic investigations, it is suggested that the brittleness of the Li2-type intermetallic compounds can be manipulated by appropriate control of composition and the corresponding electrochemical bond environment at grain boundary planes and by control of test environment. Furthermore, some examples of the materials development are described.

Role of shear stiffening in reducing hydrogenation in intermetallic compounds

2006 ◽  
Vol 89 (20) ◽  
pp. 201909 ◽  
Author(s):  
I. Jacob ◽  
M. Bereznitsky ◽  
O. Yeheskel ◽  
R. G. Leisure
Keyword(s):  
Intermetallic Compounds

Data Compilation, Analysis, and Access: The Role of the Computer

MRS Bulletin ◽  
1993 ◽  
Vol 18 (2) ◽  
pp. 44-49 ◽  
Author(s):  
J.H. Westbrook
Keyword(s):  
Experimental Data ◽  
Intermetallic Compounds ◽  
Experimental Observation ◽  
Materials Science ◽  
Data Compilation ◽  
Great Insight ◽  
History Of ◽  
A New Technique ◽  
Definition Of

History is replete with examples of the enormous impact of data compilations in all fields of science and technology. The advantages and opportunities such aggregations confer include:• convenience of access,• condensation and homogenization of raw data,• formats tailored for the application,• perception of patterns,• detection of errors,• definition of gaps and inconsistencies, and• basis for formulating and testing theories.The opportunities in materials science, and specifically in the subfield of alloy design, are no fewer than in other fields of science. Indeed, as I have remarked in a review of the history of the development of understanding and application of intermetallic compounds, breakthroughs in this field have usually come about not from “a new technique, a unique experimental observation, or an abstruse theory… Rather it was the amassing of a critical volume of experimental data in the literature which permitted an individual with great insight to perceive an underlying pattern not previously apparent.”

ROLE OF BARYONIC RESONANCES IN VIRTUAL PHOTON EMISSION IN ELEMENTARY AND HEAVY-ION COLLISIONS

2014 ◽  
Vol 26 ◽  
pp. 1460052 ◽  
Author(s):  
◽  
TETYANA GALATYUK
Keyword(s):  
Invariant Mass Distribution ◽  
Photon Emission ◽  
Heavy Ion ◽  
Medium Effect ◽  
Reference Spectrum ◽  
Electron Pairs ◽  
Ion Collisions ◽  
Energy Domain ◽  
First Time

The HADES experiment aims to explore strongly interacting baryon dominated matter at moderate temperatures using rare and penetrating probes. Special emphasis is put on the region of moderate beam energies where comparatively long-lived states of compressed matter are created. In the energy domain of 1–2 GeV per nucleon, HADES has measured hadrons and di-electron signals in C + C , Ar + KCl , p+p, d+p and p+ Nb collisions. For the first time the electron pairs were reconstructed from quasi-free n+p sub-reactions by detecting the proton spectator from the deuteron breakup. For the first time di-electrons radiated from cold nuclear matter in a kinematic regime, where strong medium effects are expected, have been detected. An experimentally constrained N + N reference spectrum was established. A direct comparison of the N + N reference spectrum with the e+e- invariant mass distribution measured in the heavier system Ar + KCl at 1.76 GeV/u shows an excess yield above the reference. The observation may be interpreted as the onset of an actual medium effect. We argue, that couplings between the ρ meson and the baryonic resonances are of fundamental importance in understanding dilepton spectra at SIS energies.

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