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.