Grain boundary diffusion activation energy derived from surface roughness measurements of aluminum thin films

1989 ◽  
Vol 55 (25) ◽  
pp. 2617-2619 ◽  
Author(s):  
L. L. Levenson
Keyword(s):  
Thin Films ◽  
Activation Energy ◽  
Surface Roughness ◽  
Grain Boundary ◽  
Boundary Diffusion ◽  
Grain Boundary Diffusion ◽  
Diffusion Activation Energy ◽  
Diffusion Activation ◽  
Roughness Measurements

Grain Boundary Diffusion in Co/Cu and Co/Cr Magnetic Thin Films

1993 ◽  
Vol 313 ◽  
Author(s):  
John G. Holl-Pellerin ◽  
S.G.H. Anderson ◽  
P.S. Ho ◽  
K.R. Coffey ◽  
J.K. Howard ◽  
...  
Keyword(s):  
Thin Films ◽  
Activation Energy ◽  
Diffusion Coefficient ◽  
Grain Boundary ◽  
Photoelectron Spectroscopy ◽  
Boundary Diffusion ◽  
Magnetic Thin Films ◽  
Grain Boundary Diffusion ◽  
X Ray ◽  
Before And After

ABSTRACTX-ray photoelectron spectroscopy (XPS) has been used to investigate grain boundary diffusion of Cu and Cr through 1000 Å thick Co films in the temperature range of 325°C to 400°C. Grain boundary diffusivities were determined by modeling the accumulation of Cu or Cr on Co surfaces as a function of time at fixed annealing temperature. The grain boundary diffusivity of Cu through Co is characterized by a diffusion coefficient, D0gb, of 2 × 104 cm2/sec and an activation energy, Ea,gb, of 2.4 eV. Similarly, Cr grain boundary diffusion through Co thin films occurs with a diffusion coefficient, Do,gb, of 6 × 10-2cm2/sec and an activation energy, Ea,gb of 1.8 eV. The Co film microstructure has been investigated before and after annealing by x-ray diffraction and transmission electron Microscopy. Extensive grain growth and texturing of the film occurred during annealing for Co deposited on a Cu underlayer. In contrast, the microstructure of Co deposited on a Cr underlayer remained relatively unchanged upon annealing. Magnetometer Measurements have shown that increased in-plane coercivity Hc, reduced remanence squareness S, and reduced coercive squareness S* result from grain boundary diffusion of Cu and Cr into the Co films.

Sr-Diffusion in Ce0.8Gd0.2O2-δ Layers for SOFC Application

2013 ◽  
Vol 1542 ◽  
Author(s):  
Tabea Mandt ◽  
Carsten Korte ◽  
Uwe Breuer ◽  
Alexander Weber ◽  
Mirko Ziegner ◽  
...  
Keyword(s):  
Activation Energy ◽  
Grain Boundary ◽  
Barrier Layer ◽  
Boundary Diffusion ◽  
Bulk Diffusion ◽  
Grain Boundary Diffusion ◽  
Diffusion Activation Energy ◽  
Boundary Density ◽  
Long Term Stability ◽  
Maximum Lifetime

ABSTRACTIn this study Sr2+ diffusion along Ce0.8Gd0.2O2-δ (CGO) grain boundaries is investigated. Model samples with different grain boundary densities were prepared by different thin film tech-niques. Diffusion experiments were performed by annealing and subsequent ToF-SIMS analysis. The activation energy of grain boundary diffusion is determined as 492 kJ/mol, which is 2/3 of the bulk diffusion activation energy 739 kJ/mol, deduced from literature data [1-5].The formation of an electrical blocking SrZrO3 layer due to grain boundary diffusion of Sr2+ through a CGO barrier layer may limit the long term stability of Solid Oxide Fuel Cells based on Zr0.85Y0.15O2-δ electrolytes and La0.58Sr0.4Co0.2Fe0.8O3-δ cathodes. The grain boundary diffusivity and the CGO grain boundary density highly influence the kinetic of the SrZrO3 formation. Aim of this study is to gain data for a prediction of the maximum lifetime of a SOFC system, limited by the increasing cell resistivity due to SrZrO3 formation. Specifications for the CGO barrier layer preparation concerning grain boundary density are determined.

The Activation Energy of Superplastic Flow above the Critical Temperature for Steel CrWMn

2007 ◽  
Vol 551-552 ◽  
pp. 341-345
Author(s):  
J.B. Wen ◽  
F.X. Chen ◽  
Ke Ke Zhang ◽  
Yong Shun Yang
Keyword(s):  
Activation Energy ◽  
Critical Temperature ◽  
Grain Boundary ◽  
Strain Rate ◽  
Superplastic Deformation ◽  
Boundary Diffusion ◽  
Grain Boundary Diffusion ◽  
Diffusion Activation Energy ◽  
Sensitivity Index ◽  
Deformation Activation Energy

By means of superplastic tensile test above the Ac1 temperature (γ→α transformation temperature), superplastic deformation activation energy of ultrafine-grained commercial die steel CrWMn is investigated on the basis of the Arrhenius theory equation, exp( / ) 1 ε& = Aσ m −Q RT , which indicates the resistance of the superplastic deformation. According to the Arrhenius equation, the activation energy is estimated from the log σt vs 1/T relationship at a constant of sensitivity index of strain rate. The results show that the strain rate sensitivity index is a constant and rather high at the conditions of superplastic deformation for the CrWMn steel, the activation energy for superplastic deformation of steel CrWMn above the critical temperature is 187KJ/mol, and the superplastic deformation activation energy is approached to the grain boundary diffusion activation energy of γ-Fe. This indicates that the grain boundary sliding (GBS) in superplastic deformation of CrWMn steel is controlled by grain boundary diffusion. The characters of superplastic deformation of the steel above the critical temperature, on the other hand, are also analyzed in this paper.

scholarly journals Synthesis of high-entropy alloy thin films via grain boundary diffusion–assisted solid-state alloying

2022 ◽  
Vol 207 ◽  
pp. 114302
Author(s):  
Seungjin Nam ◽  
Sang Jun Kim ◽  
Moon J. Kim ◽  
Manuel Quevedo-Lopez ◽  
Jun Yeon Hwang ◽  
...  
Keyword(s):  
Thin Films ◽  
Solid State ◽  
Grain Boundary ◽  
Boundary Diffusion ◽  
Grain Boundary Diffusion ◽  
High Entropy Alloy ◽  
High Entropy
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