Temperature Dependent Intermixing At The V/Ge(111) Interface

1985 ◽  
Vol 54 ◽  
Author(s):  
M. Del Giudice ◽  
R. A. Butera ◽  
J. J. Joyce ◽  
M. W. Ruckman ◽  
J. H. Weaver
Keyword(s):  
Activation Energy ◽  
High Resolution ◽  
Grain Boundary ◽  
Diffusion Process ◽  
Boundary Diffusion ◽  
The Other ◽  
Reaction Products ◽  
Kcal Mole ◽  
Temperature Dependent ◽  
Heterogeneous Interfaces

ABSTRACTHigh resolution core level photoemission results show the temperature evolution of the V/Ge(111) interface in the range from 300 to 600 K. Three well-defined chemical environments are present for Ge at 300K (the first is the substrate and the other two are reaction products with overall shifts of−0.5 and −0.95 eV). Increasing the temperature enhances Ge outdiffusion, and a homogeneous reacted layer forms when deposition and measurements are done isothermally at 475K. The activation energy for this diffusion process is very low (5 kcal/mole), indicating the importance of grain boundary diffusion at reacting, heterogeneous interfaces.

An Auger Electron Spectroscopic Study of the Diffusion of Sulfur and Carbon in α-Iron

1977 ◽  
Vol 31 (3) ◽  
pp. 210-213 ◽  
Author(s):  
W. E. Swartz ◽  
D. M. Holloway
Keyword(s):  
Activation Energy ◽  
Grain Boundary ◽  
Diffusion Process ◽  
Electron Spectroscopy ◽  
Auger Electron ◽  
Boundary Diffusion ◽  
Carbon Migration ◽  
Sulfur Diffusion ◽  
Kinetics Of ◽  
Arrhenius Analysis

Auger electron spectroscopy has been employed to study the diffusion of sulfur and carbon in α-iron. In the temperature range 25 to 500°C carbon preferentially segregates to the surface. From 400 to 700°C sulfur segregates to the surface while carbon is thermally desorbed. An Arrhenius analysis of the sulfur diffusion data yields an activation energy of 14.5 kcal/mol, which is consistent with a grain boundary diffusion process. The kinetics of carbon migration is complicated by the thermal desorption which makes Arrhenius analysis impossible.

Dopant Diffusion in TiSi2

1986 ◽  
Vol 77 ◽  
Author(s):  
F. M. d'Heurle ◽  
A. E. Michel ◽  
F. K. LeGoues ◽  
G. Scilla ◽  
J. T. Wetzel ◽  
...  
Keyword(s):  
Grain Boundary ◽  
Diffusion Process ◽  
Diffusion Coefficients ◽  
Boundary Diffusion ◽  
Radioactive Tracer ◽  
Lattice Diffusion ◽  
The Other ◽  
Small Diffusion ◽  
Secondary Ion ◽  
Thick Layers

ABSTRACTDopant elements, B and Ga, P, As and Sb, and Ge as well, have been implanted into thick (350–400 nm) layers of TiSi2 prepared by Ti-Si reaction. Both B and Sb appear to be immobile, this behavior is thought to result from very small solid solubilities, rather than from very small diffusion coefficients. The other elements display about the same behavior, with detectable grain boundary diffusion at temperatures as low as 600°C, and lattice diffusion becoming considerable at 750°C, so that with the cooperation of both phenomena almost complete homogenisation of these relatively thick layers occurs in 30 minutes at 800°C. Germanium is used in lieu of a Si radioactive tracer because it can be analyzed by Secondary Ion Mass Spectroscopy. Its behavior is thought to imply that there is little equilibrium adsorption of the dopant elements at the Si/TiSi2 interface. The comparable values of the diffusion coefficients for the mobile elements confirm the anticipation that the dopants move as substitutional atoms on the Si sublattice. Results obtained with some samples implanted with both dopant and Ti indicate that in these silicon-saturated suicide layers the diffusion process is not significantly affected by small changes in stoichiometry.

scholarly journals Der Einfluß der Temperatur auf die Strahlenempfindlichkeit von Ti-Bakteriophagen

1966 ◽  
Vol 21 (7) ◽  
pp. 678-690 ◽  
Author(s):  
Klaus-Otto Hermann
Keyword(s):  
Activation Energy ◽  
Total Cross Section ◽  
Cross Section ◽  
The Other ◽  
Base Substitution ◽  
Kcal Mole ◽  
Temperature Dependent ◽  
Direct Radiation ◽  
Dependent Component ◽  
Mev Protons

The radiosensitivity of dry bacteriophage was determined in vacuo at temperatures varying continuously between 100 ° and 300 °K using 2 MeV protons. Moreover, the influence of added cystamine and of base substitution by 5-bromouracil was investigated in the same range of temperatures. The variation of total cross section σ(Τ) with temperature is given by the expression:σ(T) =σ0·(1+5,3. e-EaRT) ±15 per cent.The constant σ0 is 3,3.10-12cm2 for normal Tl phage, 4,9.10-12cm2 for base substituted Tl phage, 1,3.10-12cm2 for Tl phage in presence of cystamine, and 1,6.10-12cm2 for base substituted Tl phage in presence of cystamine; Ea amounts to 1 kcal/mole in all four cases. The correlation between inactivation cross section σ and temperature T shows that two mechanisms of inactivation are present, one (σ0) being independent of temperature, the other having an activation energy of about 1 kcal/mole. The first mechanism is ascribed to direct radiation action, while the temperature dependent component probably originates from small diffusible radicals.

Coercivity Enhancement of Nd-Fe-B HDDR Powder by Grain Boundary Diffusion Process with Rare-Earth Hydride

JOM ◽  
2018 ◽  
Vol 70 (5) ◽  
pp. 661-665 ◽  
Author(s):  
Hee-Ryoung Cha ◽  
Jae-Gyeong Yoo ◽  
Youn-Kyoung Baek ◽  
Dong-Hwan Kim ◽  
Hae-Woong Kwon ◽  
...  
Keyword(s):  
Rare Earth ◽  
Grain Boundary ◽  
Diffusion Process ◽  
Boundary Diffusion ◽  
Grain Boundary Diffusion

Intergranular Coupling and Grain Isolation of Thin Co Films

1998 ◽  
Vol 517 ◽  
Author(s):  
Heng Gong ◽  
Wei Yang ◽  
David N. Lambeth ◽  
David E. Laughlin
Keyword(s):  
Grain Boundary ◽  
Thermal Instability ◽  
Boundary Diffusion ◽  
Oxidation Process ◽  
Diffusion Processes ◽  
Narrow Range ◽  
Grain Boundary Diffusion ◽  
Temperature Dependent ◽  
In Situ Diffusion

AbstractThe effects of rapid oxidation and overcoat diffusion processes on the intergranular coupling and grain isolation in thin Co films were studied. The oxidation process was found to be strongly temperature dependent. The optimal coercivities can only be achieved within a narrow range of temperatures, while further increasing the temperature incurs significant thermal instability. CrMn underlayers were confirmed to be more effective in enhancing the grain isolation by the grain boundary diffusion during the oxidation process. The oxidation process does not change the Co anisotropy, and hence the coercivity increase is appears to be a result of better grain isolation. The in-situ diffusion of Ag and Cr overcoats were also found to have siginificant effects on the grain isolation in Co and CoCr films.

scholarly journals Coercivity enhancement in heavy rare earth-free NdFeB magnets by grain boundary diffusion process

2018 ◽  
Vol 113 (15) ◽  
pp. 152402 ◽  
Author(s):  
D. Salazar ◽  
A. Martín-Cid ◽  
R. Madugundo ◽  
J. M. Barandiaran ◽  
G. C. Hadjipanayis
Keyword(s):  
Rare Earth ◽  
Grain Boundary ◽  
Diffusion Process ◽  
Boundary Diffusion ◽  
Grain Boundary Diffusion ◽  
Heavy Rare Earth ◽  
Ndfeb Magnets

scholarly journals Nd-Fe-B Magnets: The Gradient Change of Microstructures and the Diffusion Principle after Grain Boundary Diffusion Process

Materials ◽  
2019 ◽  
Vol 12 (23) ◽  
pp. 3881 ◽  
Author(s):  
Yaojun Lu ◽  
Shuwei Zhong ◽  
Munan Yang ◽  
Chunming Wang ◽  
Liuyimei Yang ◽  
...  
Keyword(s):  
Surface Layer ◽  
Grain Boundary ◽  
Diffusion Process ◽  
Shell Structure ◽  
Boundary Diffusion ◽  
Diffusion Mechanism ◽  
Temperature Stability ◽  
Grain Boundary Diffusion ◽  
Core Shell ◽  
Core Shell Structure

The diffusion of Tb in sintered Nd-Fe-B magnets by the grain boundary diffusion process can significantly enhance coercivity. However, due to the influence of microstructures at different depths, the coercivity increment and temperature stability gradually decreases with the increase of diffusion depth, and exhibit good corrosion resistance at a sub-surface layer (300–1000 μm). According to the Electron Probe Micro-analyzer (EPMA) test results and the diffusion mechanism, the grain boundary and intragranular diffusion behavior under different Tb concentration gradients were analyzed, and the diffusion was divided into three stages. The first stage is located on the surface of the magnet, which formed a thick core-shell structure and a large number of RE-rich phases. The second stage is located in the sub-surface layer, forming a uniform and continuous RE-rich phase and thin core-shell structure. The third stage is located deeper in the magnet, and the Tb enrichment only existed at the triangular grain boundary.

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