Wetting of polycrystalline MgO by molten Mg under evaporation

The concomitant wetting and evaporation behaviors of molten Mg on polycrystalline MgO surfaces were studied at temperatures 973–1173 K in a controlled Ar atmosphere using an improved sessile drop method. Representative wetting modes were identified by correlating contact angle with contact diameter and drop height. The intrinsic wettability in this nonreactive system can be characterized by the initial contact angles obtained in better precision from solution to a diffusion model. In addition, the excess free energy stored in the system and the potential energy barrier opposing the movement of the triple line were evaluated to account for the distinct “stick-slip” behavior.