Abstract
The wetting of Al2O3 and carbon coated-Al 2O3 substrates by Al and Al-2.5 at. % La and Al-3 at. % Y alloys was investigated by the sessile drop method in a dynamic vacuum of ∼ 10-5 Pa to obtain the contact angles as a function of time and temperature. In all cases, it was found that the magnitude of the contact angle decreased with both time and temperature. Minimum contact angles of 38°, 40° and 55° were obtained at 1300°C and holding time of 4500 seconds for Al-2.5 at. % La, Al and Al-3 at. % Y respectively on carbon coated-Al 2O3 versus 82° for Al on uncoated Al2O 3. The formation of both oxides and carbides is thermodynamically favorable under the conditions used. The observation of ridges at the boundary of the liquid alloy droplet suggested that reactive wetting had occurred with the carbon coated-Al2O3 substrates. Probable mechanisms for the observed carbon-enhanced wettability in the system and some processing details are discussed.
Original language | English |
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Pages | 317-327 |
Number of pages | 11 |
State | Published - 2004 |
Event | Advances in Ceramic Matrix Composites IX, Proceedings - Nashville, TN, United States Duration: Apr 27 2003 → Apr 30 2003 |
Conference
Conference | Advances in Ceramic Matrix Composites IX, Proceedings |
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Country/Territory | United States |
City | Nashville, TN |
Period | 04/27/03 → 04/30/03 |