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Cation Diffusion in Single‐Crystal and Polycrystalline BeO
Author(s) -
AUSTERMAN STANLEY B.,
WAGNER J. W.
Publication year - 1966
Publication title -
journal of the american ceramic society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.9
H-Index - 196
eISSN - 1551-2916
pISSN - 0002-7820
DOI - 10.1111/j.1151-2916.1966.tb13216.x
Subject(s) - crystallite , diffusion , materials science , impurity , crystallography , single crystal , condensed matter physics , grain boundary , crystal (programming language) , hexagonal crystal system , effective diffusion coefficient , surface diffusion , grain boundary diffusion coefficient , chemistry , thermodynamics , microstructure , physics , medicine , organic chemistry , radiology , computer science , magnetic resonance imaging , programming language , adsorption
The diffusion of Be was measured in single crystals of BeO in directions normal and parallel to the hexagonal c axis. The diffusion coefficients, D , in the two directions were nearly equal to each other. The values of D , measured between 1500° and 2000°C were quite similar to values reported previously for high‐density, high‐purity, polycrystalline BeO. The single‐crystal data, taken in conjunction with polycrystalline data, show that the observed diffusion in polycrystalline BeO proceeds entirely by volume diffusion with no significant diffusion along grain boundaries, although there is some evidence of rapid surface diffusion along microcracks in the surface. The data are interpreted in terms of extrinsic impurity‐dependent diffusion via mobile vacancies.