OPTIMIZATION OF WETTABILITY AND ADHESION IN REACTIVE NICKEL-BASED ALLOYS ALUMINA SYSTEMS BY A THERMODYNAMIC APPROACH/

Optimization of wetting and adhesion in metal/oxide systems can be ach ieved by using solutes to control the chemistry of the interfaces and the thickness of reaction product layers. This approach is illustrated by results obtained for Ni alloy/Al2O3 systems. Wettability experimen ts are performed by the sessile drop technique under high vacuum or a static neutral gas atmosphere. Interfacial chemistry and morphology ar e determined using scanning electron microscopy and electron microprob e analysis. Adhesion is qualitatively characterized by the type of fra cture observed during cooling of sessile drop samples.