A contribution to the analysis of grain boundary diffusion measurements

1968 ◽  
Vol 46 (13) ◽  
pp. 1511-1521 ◽  
Author(s):  
Jaroslav Kučera
Keyword(s):  
Diffusion Coefficient ◽  
Grain Boundary ◽  
Penetration Depth ◽  
Boundary Diffusion ◽  
Diffusion Problem ◽  
Grain Boundary Diffusion ◽  
High Concentration ◽  
Low Concentration ◽  
Depth Measurement ◽  
Sectioning Method

The Whipple and Suzuoka exact solutions of the grain boundary diffusion problem have been extended to the Gruzin method. The penetration curves for these two solutions were evaluated numerically using the method of penetration depth measurement, the sectioning method, and the Gruzin method. With the results obtained, relationships are given which make the evaluation of grain boundary diffusion coefficients in the low concentration range (up to 0.005%) comparatively easy. For all three experimental methods the Whipple and Suzuoka solutions have been compared. The comparison for the method of penetration depth measurement was only possible in the low concentration range. When evaluating the data in the low concentration range, using Whipple's or Suzuoka's solutions, approximately the same values of grain boundary coefficient are obtained, irrespective of the experimental method used. A comparison of the solutions using the sectioning and the Gruzin methods in the high concentration range (100%–0.1%) shows that the Gruzin method is not sensitive to the mathematical model used for treating the experimental data. The application of Whipple's solution to the data corresponding to Suzuoka's model gives higher values of the volume diffusion coefficient and slightly higher values of the grain boundary diffusion coefficient in the sectioning method and vice versa.

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.

Zinc Self-Diffusion in ZnO

2005 ◽  
Vol 237-240 ◽  
pp. 163-168 ◽  
Author(s):  
M.A.N. Nogueira ◽  
Antônio Claret Soares Sabioni ◽  
Wilmar Barbosa Ferraz
Keyword(s):  
Diffusion Coefficient ◽  
Grain Boundary ◽  
Diffusion Coefficients ◽  
Boundary Diffusion ◽  
Volume Diffusion ◽  
Grain Boundary Diffusion ◽  
Polished Surface ◽  
Self Diffusion ◽  
Zinc Diffusion ◽  
Diffusion Profiles

This work deals with the study of zinc self-diffusion in ZnO polycrystal of high density and of high purity. The diffusion experiments were performed using the 65Zn radioactive isotope as zinc tracer. A thin film of the tracer was deposited on the polished surface of the samples, and then the diffusion annealings were performed from 1006 to 1377oC, in oxygen atmosphere. After the diffusion treatment, the 65Zn diffusion profiles were established by means of the Residual Activity Method. From the zinc diffusion profiles were deduced the volume diffusion coefficient and the product dDgb for the grain-boundary diffusion, where d is the grain-boundary width and Dgb is the grain-boundary diffusion coefficient. The results obtained for the volume diffusion coefficient show good agreement with the most recent results obtained in ZnO single crystals using stable tracer and depth profiling by secondary ion mass spectrometry, while for the grain-boundary diffusion there is no data published by other authors for comparison with our results. The zinc grain-boundary diffusion coefficients are ca. 4 orders of magnitude greater than the volume diffusion coefficients, in the same experimental conditions, which means that grain-boundary is a fast path for zinc diffusion in polycrystalline ZnO.

Pressure, temperature, water content, and oxygen fugacity dependence of the Mg grain-boundary diffusion coefficient in forsterite

2018 ◽  
Vol 103 (9) ◽  
pp. 1354-1361 ◽  
Author(s):  
Hongzhan Fei ◽  
Sanae Koizumi ◽  
Naoya Sakamoto ◽  
Minako Hashiguchi ◽  
Hisayoshi Yurimoto ◽  
...  
Keyword(s):  
Diffusion Coefficient ◽  
Grain Boundary ◽  
Water Content ◽  
Oxygen Fugacity ◽  
Boundary Diffusion ◽  
Grain Boundary Diffusion ◽  
Boundary Diffusion Coefficient ◽  
Temperature Water

Boron Diffusion in Polycrystalline Silicon

1986 ◽  
Vol 76 ◽  
Author(s):  
Moustafa Y. Ghannam ◽  
Robert W. Dutton ◽  
Steven W. Novak
Keyword(s):  
Grain Size ◽  
Diffusion Coefficient ◽  
Grain Boundary ◽  
Grain Boundaries ◽  
Polycrystalline Silicon ◽  
Boundary Diffusion ◽  
Crystalline Silicon ◽  
Unit Area ◽  
Grain Boundary Diffusion ◽  
Boron Diffusion

ABSTRACTThe diffusion of boron in ion implanted LPCVD polycrystalline silicon is shown to be dominated by grain boundary diffusion at low and moderate concentrations. The diffusion coefficient is 2 to 3 orders of magnitude larger than its value in crystalline silicon. In preannealed polysilicon, the boron diffusion coefficient is found to be 30% smaller than in polysilicon annealed after implantation. This reflects the effect of the grain size in the diffusion coefficient since preannealed polysilicon has larger grains and smaller density of grain boundaries per unit area.

Grain Boundary Diffusion in Nanocrystalline Materials Produced by Severe Plastic Deformation

2015 ◽  
Vol 5 ◽  
pp. 129-143 ◽  
Author(s):  
Vladimir V. Kondratyev ◽  
Alexander G. Kesarev ◽  
Ilya L. Lomaev
Keyword(s):  
Grain Boundary ◽  
Boundary Diffusion ◽  
Diffusion Theory ◽  
Diffusion Problem ◽  
Grain Boundary Diffusion ◽  
Diffusion Activation Energy ◽  
Enhanced Diffusion ◽  
Diffusional Mass ◽  
Diffusion Enhancement ◽  
The One

The model of diffusional mass transfer in the medium with a strong spatial dependence of diffusivity and its application to the grain boundary (GB) diffusion problem is presented. A significant decrease of diffusion activation energy is shown to take place takes place in the vicinity of non-equilibrium grain boundary, which leads to the formation of a region of enhanced diffusion. The generalization of grain boundary diffusion theory is given which accounts for the diffusion enhancement near GB. An original mathematical approach is developed and general asymptotic solutions of the one-and two-dimensional diffusion problems are derived for two types of diffusant source — constant and instant. The applicability domain of presented model is discussed.

scholarly journals Exploration of the Transition from Harrison Type-A Kinetics to Type-B Kinetics Regimes in Grain Boundary Diffusion

2008 ◽  
Vol 273-276 ◽  
pp. 425-430 ◽  
Author(s):  
Irina V. Belova ◽  
Graeme E. Murch
Keyword(s):  
Grain Boundary ◽  
Transition Point ◽  
Boundary Diffusion ◽  
Diffusion Length ◽  
3D Structure ◽  
Type A ◽  
Tracer Diffusion ◽  
Diffusion Problem ◽  
Grain Boundary Diffusion ◽  
Type B

We model the grain boundary tracer diffusion problem by constructing a 3D structure consisting of cubic grains each of equal volume. We build the structure in such a way that no four cubes have a common edge. It is shown that the transition point between Harrison Type-A and Type-B kinetics regimes occurs at a diffusant diffusion length roughly an order of magnitude smaller than for the extensively studied case of parallel grain boundary slabs. For two dimensional squares the transition point occurs at a diffusion length roughly a factor of five smaller than for parallel grain boundary slabs. Thus we can draw the conclusion that dimensionality and geometric shape are both important factors in the parametric analysis of the grain boundary diffusion problem.

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