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Grain‐Boundary Diffusion of Cr in Pure and Y‐Doped Alumina
Author(s) -
BeduAmissah K.,
Rickman J. M.,
Chan H. M.,
Harmer M. P.
Publication year - 2007
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.1551-2916.2007.01584.x
Subject(s) - yttrium , doping , arrhenius equation , grain boundary diffusion coefficient , diffusion , electron microprobe , chromium , analytical chemistry (journal) , grain boundary , materials science , activation energy , effective diffusion coefficient , microprobe , mineralogy , chemistry , thermodynamics , metallurgy , microstructure , physics , medicine , optoelectronics , chromatography , radiology , magnetic resonance imaging , oxide
The diffusive transport of chromium in both pure and Y‐doped fine‐grained alumina has been investigated over the temperature range 1250°–1650°C. From a quantitative assessment of the chromium diffusion profile in alumina, as obtained from electron microprobe analysis, it was found that yttrium doping retards cation diffusion in the grain‐boundary regime by over an order of magnitude. The Arrhenius equations for the undoped and Y‐doped samples were determined to be: δ D b =(4.77±0.24) × 10 −7 exp (−264.78±47.68 (kJ/mol)/RT)(cm 3 /s) and δD b =(6.87±0.18) × 10 −8 exp (−284.91±42.57 (kJ/mol)/RT)(cm 3 /s), respectively. Finally, to elucidate the mechanism for this retardation, the impact of yttrium doping on diffusion activation energies and prefactors was examined.