Wetting and evaporation behaviors of molten Mg on partially oxidized SiC substrates

The wetting and evaporation behaviors of molten Mg drops on pressureless-sintered SiC surfaces were studied in a flowing Ar atmosphere at 973-1173 K by an improved sessile drop method. The initial contact angles are between 83° and 76°, only mildly depending on temperature. The formation of a ridge at the triple junction as a result of reaction between molten Mg and the SiO₂ film on the SiC surface pins the triple line and leads to a constant contact diameter mode during the entire evaporation process. Moreover, the diffusion coefficients of the Mg vapor at different temperatures were evaluated based on a simple model.