Ion-Probe Measurement of Oxygen Self-Diffusion in Single-Crystal Al2O3

Anion self‐diffusion coefficients normal to (1102) were obtained for single‐crystal Al2O3 in a 1.3 × 10 3 N/m2 (10−5 torr) vacuum at 1585° to 1840°C. Tracer was supplied from an initial 650 to 1300 A Al218O3 layer produced by the oxidation of vapor‐deposited Al metal films in an 18O2 atmosphere at 5...

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Bibliographic Details
Published in:Journal of the American Ceramic Society 1980-01, Vol.63 (1-2), p.88-92
Main Authors: REED, DAVID J., WUENSCH, B. J.
Format: Article
Language:English
Online Access:Get full text
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Summary:Anion self‐diffusion coefficients normal to (1102) were obtained for single‐crystal Al2O3 in a 1.3 × 10 3 N/m2 (10−5 torr) vacuum at 1585° to 1840°C. Tracer was supplied from an initial 650 to 1300 A Al218O3 layer produced by the oxidation of vapor‐deposited Al metal films in an 18O2 atmosphere at 520°C. Concentration gradients extended over depths of 3000 to 5000 A and were measured by mass spectrometry of material sputtered from the samples with a beam of Ar+ ions. Crystals which had not been preannealed to remove surface damage displayed enhanced diffusion. Diffusion coefficients from preannealed crystals may be described by D0=6.4×105cm2/s, with an activation energy of 188 ± 7 kcal/mol. The diffusion is interpreted as an extrinsic vacancy mechanism.
ISSN:0002-7820
1551-2916
DOI:10.1111/j.1151-2916.1980.tb10655.x