Exafs Studies of Grain Boundary Diffusion and Segregation

1986 ◽  
Vol 77 ◽  
Author(s):  
S. M. Heald ◽  
H. Chen ◽  
J. M. Tranquada
Keyword(s):  
Thin Film ◽  
Solid State ◽  
Grain Boundary ◽  
Grain Boundaries ◽  
Boundary Diffusion ◽  
Structural Information ◽  
Solid State Diffusion ◽  
Interface Reactions ◽  
Tin Bronze ◽  
State Diffusion

ABSTRACTThe dominant pathway for thin film interdiffusion and interface reactions is often via grain boundaries. We have made EXAFS measurements of grain boundary constituents for two systems: interdiffusion in Ag-Au bilay-ers and solid state reaction of Nb with a copper-tin bronze to form Nb3Sn. The Ag-Au results indicate that Au in saturated Ag grain boundaries has an environment similar to a dilute Au in Ag solution with reduced coordination. For the Nb-bronze reaction, the results for the Cu environment indicate distinct changes in the grain boundary environment when small amounts of Ti, Hf, Zr, and Ta are added to the starting Nb. Both results demonstrate the ability of EXAFS to probe grain boundary environments, and to provide important structural information in understanding solid state diffusion and interdiffusion in thin film systems.

Diffusion at Short Circuits: State of the Art

2010 ◽  
Vol 297-301 ◽  
pp. 1267-1283 ◽  
Author(s):  
Boris S. Bokstein
Keyword(s):  
Solid State ◽  
Grain Boundary ◽  
Boundary Diffusion ◽  
Boundary Segregation ◽  
Grain Boundary Diffusion ◽  
Polycrystalline Materials ◽  
Solid State Diffusion ◽  
Diffusion Parameters ◽  
State Diffusion ◽  
Fisher Model

Evidence for solid-state diffusion (the second half of the 19th century). The first measurements of solid state diffusion (W. Roberts-Austen, 1896–1922). The first tracer experiments to determine the solid-state diffusion (G. von Hevesy, 1913–1923). The first evidence of accelerated diffusion in polycrystalline materials (1924–1935). Autoradiographic studies of grain boundary diffusion (50s of 20th century). The first quantitative experimental and theoretical studies of the “short circuiting” diffusion (beginning from 1949, D. Turnbull and R. Hoffman – General Electric Research Lab.): radiotracer serial sectioning method, the Fisher model (1951) for grain boundary diffusion, exact solutions and developments of the Fisher model (1954–1963). The progress in the experimental methods for determination of grain boundary diffusion data and results of measurements for different metallic systems (up to date). The measurements of grain boundary diffusion parameters in the B and C regimes. Grain boundary diffusion and grain boundary segregation. Nonlinear segregation effects. Structural effects of grain boundary diffusion. Diffusion in bicrystals. Diffusion in nanocrystals. Computer simulation of grain boundary diffusion. Mechanisms of grain boundary diffusion.

Grain boundary Diffusion of Ni through Pd2Si

1983 ◽  
Vol 25 ◽  
Author(s):  
E. C. Zingu ◽  
J. W. Mayer
Keyword(s):  
Thin Film ◽  
Activation Energy ◽  
Grain Boundary ◽  
Grain Boundaries ◽  
Boundary Diffusion ◽  
Rutherford Backscattering Spectrometry ◽  
High Mobility ◽  
Grain Boundary Diffusion ◽  
Rutherford Backscattering

ABSTRACTInterdiffusion in the Si<100>/Pd2Si/Ni and Si<111>/Pd2Si/Ni thin film systems has been investigated using Rutherford backscattering spectrometry. Nickel is found to diffuse along the grain boundaries of polycrystalline Pd2Si upon which it accumulates at the Si<100>Pd2Si interface. The high mobility of Ni compared to that of si suggests that Pd diffuses faster than Si along the Pd2Si grain boundaries. An activation energy of 1.2 eV is determined for Ni grain boundary diffusion in Pd2Si.

Gold to aurostibite transformation and formation of Au-Ag-Sb phases: the Krásná Hora deposit, Czech Republic

2017 ◽  
Vol 81 (4) ◽  
pp. 987-999 ◽  
Author(s):  
Jiří Zachariáš ◽  
Matěj Němec
Keyword(s):  
Czech Republic ◽  
Solid State ◽  
Grain Boundaries ◽  
Native Gold ◽  
Diffusion Processes ◽  
Solid State Diffusion ◽  
State Diffusion

AbstractRare phases of the Au–Ag–Sb system were recognized in the Krásná Hora Sb-Au deposit (Sb 1.5–3 wt.%; Au 3–5 ppm), Czech Republic which correspond to auriferous dyscrasite (up to 7 at.% Au), auriferous allargentum (up to 34 at.% Au), and an unnamed phase with composition similar to the eutectics (E1, E2) of the experimental Au–Ag–Sb system. The dominant ore mineral is stibnite with rare native antimony, native gold and a Ag-Au alloy. Textural relationships are well established: stibnite (early) →gold → aurostibite → native antimony (late). Gold is present in four generations: Au-1 (0–15 at.% Ag) is the most abundant type; Au-2 (20–70 at.% Ag) forms thin rims along intra-grain boundaries of Au-1; Au-3 and Au-4 are rare and almost pure (∼0 at.% Ag). The formationof most of the Au-2 and of Au-Ag-Sb phases is associated with Ag-mobilization coupled with the Au-1 to aurostibite transformation via dissolution-precipitation and solid-state diffusion processes at temperatures <200°C.

Growth of Silicon Carbide Filaments in Multicrystalline Silicon for Solar Cells

2009 ◽  
Vol 156-158 ◽  
pp. 35-40 ◽  
Author(s):  
Hans Joachim Möller ◽  
Claudia Funke ◽  
Jan Bauer ◽  
S. Köstner ◽  
H. Straube ◽  
...  
Keyword(s):  
Silicon Carbide ◽  
Solar Cells ◽  
Solid State ◽  
Grain Boundaries ◽  
Bulk Material ◽  
Casting Process ◽  
Carbon Diffusion ◽  
Solid State Diffusion ◽  
State Diffusion ◽  
Solid Liquid Interface

This work introduces two different approaches to explain the growth of silicon carbide (SiC) filaments, found in the bulk material and in grain boundaries of solar cells made from multicrystalline (mc) silicon. These filaments are responsible for ohmic shunts. The first model proposes that the SiC filaments grow at the solid-liquid interface of the mc-Si ingot, whereas the second model proposes a growth due to solid state diffusion of carbon atoms in the solid fraction of the ingot during the block-casting process. The melt interface model can explain quantitatively the observed morphologies, diameters and mean distances of SiC filaments. The modeling of the temperature- and time-dependent carbon diffusion to a grain boundary in the cooling ingot shows that solid state diffusion based on literature data is not sufficient to transport the required amount of approximately 3.4  1017 carbon atoms per cm2 to form typical SiC filaments found in grain boundaries of mc-Si for solar cells. However, possible mechanisms are discussed to explain an enhanced diffusion of carbon to the grain boundaries.

Formation of Amorphous Interlayers by Solid–State Diffusion in Ti Thin Films on Si–ge Layers on Silicon and Germanium

1995 ◽  
Vol 379 ◽  
Author(s):  
J.B. Lai ◽  
C.S. Liu ◽  
L.J. Chen ◽  
J.Y. Cheng
Keyword(s):  
Thin Film ◽  
Solid State ◽  
Electron Spectroscopy ◽  
Auger Electron ◽  
The Other ◽  
Solid State Diffusion ◽  
Formation Temperature ◽  
Transmission Electron ◽  
State Diffusion ◽  
Silicon And Germanium

ABSTRACTThe formation of amorphous interlayers (a–interlayers) by solid–state diffusion in ultrahigh vacuum deposited polycrystalline Ti thin film on germanium and Sil-xGex alloys grown on (001)Si has been investigated by transmission electron microscopy and Auger electron spectroscopy.Amorphous interlayers, less than 2 nm in thickness, were observed to form in all as–deposited samples. The growth of a–interlayers was found to vary non–monotonically with the composition of Si–Ge alloys in annealed samples. On the other hand, the formation temperature of crystalline phase was found to decrease with the Ge content. The results are compared with that of the Ti/Si system. The formation mechanism are discussed in terms of thermodynamic and kinetic factors.

scholarly journals Applications of Ab Initio Modeling to Materials Science: Grain Boundary Cohesion and Solid State Diffusion

2004 ◽  
Author(s):  
GA Young ◽  
R Najafabadi ◽  
W Strohmayer ◽  
J Vollmer ◽  
C Thompson ◽  
...  
Keyword(s):  
Solid State ◽  
Grain Boundary ◽  
Ab Initio ◽  
Materials Science ◽  
Solid State Diffusion ◽  
Ab Initio Modeling ◽  
State Diffusion
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