Oxygen induced interfacial phenomena during wetting of alumina by liquid aluminium
✍ Scribed by George Levi; Wayne D Kaplan
- Publisher
- Elsevier Science
- Year
- 2002
- Tongue
- English
- Weight
- 347 KB
- Volume
- 50
- Category
- Article
- ISSN
- 1359-6454
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✦ Synopsis
Sessile drop experiments of liquid Al on sapphire (α-Al 2 O 3 ) were conducted under a low pressure (10 Ϫ3 Torr) controlled Ar atmosphere as a function of oxygen partial pressure, temperature and/or time. Microstructural investigations of the samples from the experiments indicated that two different dominant processes occur at the liquid Alsapphire interface: epitaxial growth of new α-Al 2 O 3 layers on the sapphire substrate at temperatures below Ϸ1100°C and dissolution of the sapphire substrate at temperatures above Ϸ1100°C. Possible mechanisms by which oxygen affects wetting and adhesion of liquid Al on sapphire are examined. The non-wetting to wetting transition in this system may be explained by formation of an oxygen-rich interphase at the liquid Al-sapphire interface. It is concluded that dissolution of sapphire under Al oxidation conditions is capillary driven.