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Pore Drag and Pore‐Boundary Separation in Alumina
Author(s) -
Rödel Jürgen,
Glaeser Andreas M.
Publication year - 1990
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.1151-2916.1990.tb06453.x
Subject(s) - materials science , sintering , diffusion , crystallite , pore water pressure , drag coefficient , doping , drag , mineralogy , analytical chemistry (journal) , composite material , thermodynamics , chemistry , chromatography , metallurgy , geology , optoelectronics , physics , geotechnical engineering
Microdesigned interfacial pore structures were used to study pore drag and pore‐boundary separation in Al 2 O 3 . This approach allows the creation of pore arrays containing pores of controlled size and spacing at well‐defined singlecrystal seed/polycrystalline matrix interfaces, and enables experimental determination of the peak pore velocity. From the peak pore velocity, values of the surface diffusion coefficient pertinent to sintering can be extracted. At 1600°C, the surface diffusion coefficient is ∼1 × 10 −7 cm 2 /s for undoped Al 2 O 3 and ∼4 × 10 −7 cm 2 /s for MgO‐doped Al 2 O 3 . The values appear to be insensitive to the seed orientation for the two seed orientations studied. The results suggest a strong influence of pore spacing on the separation condition in undoped Al 2 O 3 , and a diminished influence in MgO‐doped Al 2 O 3 . Quantitative agreement between theoretically predicted and experimentally observed separation/attachment conditions was obtained.