ISSN:
1573-4889
Keywords:
easy diffusion paths
;
Al2O3 films
;
γ-Al2O3 nucleation sites
;
amorphous film
Source:
Springer Online Journal Archives 1860-2000
Topics:
Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
Notes:
Abstract Thermal oxide films grown on electropolished aluminum specimens have been investigated by transmission electron microscopy of stripped oxide films and ultramicrotomed sections. Particular attention has been focused on the nucleation sites γ-Al 2 O 3 crystals and the relationship of such sites to surface features on the electropolished aluminum surface. It is evident that “easy paths” for the diffusion of oxygen, or the nucleation sites of γ-Al 2 O 3 crystals, are not distributed randomly over the electropolished aluminum surface, but form preferentially in the amorphous oxide layer grown over preexisting metal ridges. Thus, the diffusion of molecular oxygen through cracks in the amorphous oxide layer represents the most realistic and acceptable basis for explaining the local growth of the γ-Al 2 O 3 crystals in thermal oxide films on aluminum, although the cracks have not yet been observed directly.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00664713
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