Journal of the American Ceramic Society · 2001 · 34 citations · 11 references
Natural SciencesChemistryMaterials SciencePhysical ChemistrySpectroscopyTransport PhenomenaDiffusion In SolidsMass TransferMass TransportOxygen TransportSolid-state DiffusionTransport PropertiesAnisotropyDiffusion Activation EnergyDiffusion CoefficientsDiffusion MechanismsEnthalpyOxygen DiffusionSecondary Ion Mass SpectrometryTracer Diffusion
Oxygen 18 O tracer diffusion in Czochralski‐grown mullite single crystals is investigated along [010] and [001]. Oxygen diffusion coefficients range between ∼5 × 10 −20 m 2 /s (1250°C) and ∼9 × 10 −18 m 2 /s (1525°C). The data does not show any significant anisotropy. The values of the activation enthalpy (4.5 eV) and of the activation entropy ((3.4 ± 1.6) k B , where k B is the Boltzmann constant) suggest that the atomic transport occurs via thermally activated vacancies.
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