Au–Sapphire (0001) solid–solid interfacial energy

This work presents an experimental methodology for the measurement of interfacial energy (γ_SP) and work of adhesion (W _ad) of a metal–ceramic interface. A thin Au film was dewetted on the basal surface of sapphire substrates to form submicron-sized particles, which were analyzed using the Winterbottom method to determine the equilibrated particle–substrate solid–solid interfacial energy. Electron microscopy showed that a large portion of the particles contained grain boundaries, while all of the single crystalline particles had three distinct morphologies and orientations with the substrate. Two orientation relationships were determined from transmission electron microscopy, for which the interfacial energy in air at 1000 °C was determined: Au (111)–sapphire (0001): γ_SP = 2.15 ± 0.04 J/m², W _ad = 0.49 ± 0.04 J/m²; Au (100)–sapphire (0001): 2.18 ± 0.06 J/m², W _ad = 0.55 ± 0.07 J/m².