High-Temperature Wetting and the Work of Adhesion in Metal/Oxide Systems

This article reviews data on wetting and the work of adhesion in metal/oxide systems at high temperatures in terms of proposed mutual adsorption models. Favorable adsorption energies can induce changes, especially near the high- and low-p(O2) limits of the coexistence range that often mimic bulk oxidation or reduction reactions. However, in some systems, an intermediate range of p(O2) exists wherein all the interfaces are stoichiometric and the contact angle and work of adhesion are independent of p(O2). A revision of existing data for several pure metal/Al2O3 systems affirms predicted trends and reveals that the contact angle is 110°–130° at the plateau and drops to or below 90° at the high- and low-p(O2) limits. This article also compares the data with recent advances in the characterization and modeling of metal-ceramic interfaces at the atomic level.