Nature of interfacial phenomena at copper-titanium/alumina and copper-oxygen/alumina interfaces

Experiments with liquid copper-titanium alloy and copper-3 w/o oxygen alloys in contact with polycrystalline alumina in both a sessile drop and capillary rise configuration are used to demonstrate that reactive metals such as copper-titanium alloys in contact with ceramic surfaces exhibit a complex wetting behavior. Although both liquids form acute contact angles in the sessile drop configuration, the copper-titanium liquid does not rise to significant heights in a capillary tube. The observed acute angle morphology of liquid copper-titanium alloys in the sessile drop experiment is a consequence of reaction layer formation, with gravity assisting the liquid to spread into an acute angle configuration. In contrast, in addition to forming an acute angle in the sessile drop configuration, the copper-oxygen alloys also instantly infiltrate micro-capillary channels in alumina.