Ion-probe measurement of oxygen self-diffusion in single-crystal Al sub 2 O sub 3

Anion self-diffusion coeffs. normal to (1102) were obtained for single-crystal Al sub 2 O sub 3 in a 1.3 multiplied by 10 sup minus 3 N/m sup 2 (10 sup minus 5 torr) vacuum at 1585-1840 Degrees C. Tracer was supplied from an initial 650-1300 Angstroms Al sub 2 sup 18 O sub 3 layer produced by the ox...

Full description

Saved in:
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 Bernhardt, J
Format: Article
Language:English
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:Anion self-diffusion coeffs. normal to (1102) were obtained for single-crystal Al sub 2 O sub 3 in a 1.3 multiplied by 10 sup minus 3 N/m sup 2 (10 sup minus 5 torr) vacuum at 1585-1840 Degrees C. Tracer was supplied from an initial 650-1300 Angstroms Al sub 2 sup 18 O sub 3 layer produced by the oxidation of vapor-deposited Al metal films in an sup 18 O sub 2 atm at 520 Degrees. Concentration gradients extended over depths of 3000-5000 Angstroms 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 coeffs. from preannealed crystals may be described by D sub 0=6.4 multiplied by 10 sup 5 cm sup 2/s, with an activation energy of 188 plus or minus 7 kcal/mol. The diffusion is interpreted as an extrinsic vacancy mechanism.
ISSN:0002-7820