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Ba 2 Ti 9 O 20 Phase Equilibria
Author(s) -
O'BRYAN HENRY M.,
THOMSON JOHN
Publication year - 1983
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.1151-2916.1983.tb09970.x
Subject(s) - rutile , phase (matter) , barium , materials science , stoichiometry , ceramic , mineralogy , kinetics , oxygen , analytical chemistry (journal) , chemical engineering , chemistry , metallurgy , organic chemistry , engineering , physics , chromatography , quantum mechanics
The heterogeneous phase distribution found in Ba 2 Ti 9 O 20 ceramic resonators results from a temperature‐dependent phase boundary and slow reaction kinetics. When sintered at 1350°C or higher in oxygen the Ba 2 Ti 9 O 20 phase becomes slightly reduced and barium‐rich. Thus a stoichiometric composition forms rutile and ″Ba 2 Ti 9 O 20 'phase. On slow cooling the excess barium diffuses to the oxygen‐rich surface where it reacts to form an envelope of rutile‐free material surrounding a core containing a small amount of rutile.