The wettability and adhesion of alpha-Al2O3 single crystals with different crystallographic orientations by liquid Al and Cu were investigated using an improved sessile drop method. It was demonstrated that the alpha-Al2O3 surface orientation has a noticeable effect on the wettability and adhesion of the Al/alpha-Al2O3 system, but a negligible effect for the Cu/alpha-Al2O3 system. The results were explained by the interfacial atomic bonding mechanism with consideration of the alumina surface atomic configurations. (C) 2005 Springer Science + Business Media, Inc.