Influence of Oxygen Partial Pressure and Oxygen Content on the Wettability in the Copper–Oxygen–Alumina System

Abstract

The influence of oxygen on the wetting behavior of copper on single‐crystal Al2O3 has been studied. By controlling the oxygen partial pressure (pO2) and oxygen content in the copper simultaneously, contact angle can be varied between 125° and 22°. Evaluation of the Gibbs adsorption equation for the liquid/solid interface at 1300°C suggests that adsorption of a Cu‐O complex at that interface plays a key role in promoting wetting. Formation of CuAlO2 and dissolution of Al2O3 in the melt also influence the contact angle, especially in the range of pO2 > 10−5 bar (1 Pa).