Abstract
Wettability of sintered Al2O3 plates by Al and Al-Ti alloys containing up to 5 mass% Ti was studied by means of sessile drop method in considering various oxygen partial pressures (Po2) in ambient atmosphere. Results obtained are summarized as follows:
(1) Wetting angle between pure Al and sintered Al2O3 plates at 1373 K in vacuum (Po2=1.4×10-1-1.7×10-4 Pa), decreased with the increase of holding time. This corresponds to the primary spreading process, i.e., dissolution of Al2O3 in liquid Al determines the time-dependent wetting between pure Al and sintered Al2O3 plates.
(2) Surface tension of liquid pure Al increased with the increase of Po2 in atmosphere. On the contrary, interface energy between liquid pure Al and solid sintered Al2O3 plates decreased with the increase of Po2. No influence of Po2 on wetting angle was found.
(3) Addition of Ti to liquid Al did not change it's surface tension, however, a slight decrease in work of adhesion of liquid Al-Ti alloy to sintered Al2O3 plates, with Ti content up to 3 mass%Ti, and an increase at 5 mass% Ti were observed.
(4) Fine granular oxide (Al2TiO5) was found to form at the interfaces between Al-Ti alloys and sintered Al2O3 plates, but did not alter the wettability in this system.
