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Cation Interdiffusion in Polycrystalline Calcium and Strontium Titanate
Author(s) -
Butler Elizabeth Patricia,
Jain Himanshu,
Smyth Donald M.
Publication year - 1991
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.1151-2916.1991.tb06923.x
Subject(s) - strontium , strontium titanate , calcium titanate , impurity , diffusion , calcium , titanate , crystallite , vacancy defect , solubility , solid solution , inorganic chemistry , mineralogy , materials science , analytical chemistry (journal) , stoichiometry , alkaline earth metal , chemistry , ceramic , crystallography , metal , thermodynamics , metallurgy , nanotechnology , thin film , physics , organic chemistry , chromatography
A method has been developed to study bulk lattice interdiffusion between calcium and strontium titanate by fabrication of a diffusion couple using cosintering. The measured interdiffusion coefficients, D̃ ( C ), indicate that strontium impurity diffusion in calcium titanate occurs at a faster rate than calcium impurity diffusion in strontium titanate. These interdiffusion coefficients are composition independent when the concentration of the calcium cation exceeds that of the strontium cation; otherwise D̃( C ) is strongly composition dependent. Investigations into the effect of cation nonstoichiometry give results that are consistent with a defect incorporation reaction in which excess TiO 2 , within the solid solubility limit, produces A‐site cation vacancies as compensating defects. The interdiffusion coefficients increase with increasing concentrations of TiO 2 , so it is concluded that interdiffusion of these alkaline‐earth cations in their titanates occurs via a vacancy mechanism.