Premium
Chemical Diffusion in Polycrystalline Al 2 O 3
Author(s) -
WANG H. A.,
KRÖGER F. A.
Publication year - 1980
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.1151-2916.1980.tb09846.x
Subject(s) - feal , grain boundary , diffusion , crystallite , oxygen , materials science , grain boundary diffusion coefficient , oxygen pressure , analytical chemistry (journal) , mineralogy , crystallography , metallurgy , chemistry , thermodynamics , intermetallic , microstructure , alloy , physics , organic chemistry , chromatography
Chemical diffusion in poly crystalline α‐Al 2 O 3 doped with Ti or Fe was studied through the movement of a color front on oxidation of reduced samples. The diffusion is faster in polycrystal‐line than in single‐crystal material. The oxygen pressure dependence of the rate of diffusion indicates that neutral interstitial oxygen is the major mobile species at the grain boundaries. A theory is presented which accounts for the data and explains the difference in the rates of oxidation and reduction and their dependence on oxygen pressure. Grain boundaries with precipitates of FeAl 2 O 4 or TiAl 2 O 5 appear to transport oxygen faster than clean boundaries.