Pinning–depinning behavior in the wetting of (0 0 0 1) α-Al2O3 single crystal by molten Mg

Wetting of (0 0 0 1) α-Al2O3 single crystal by molten Mg was studied by an improved sessile drop method in a purified flowing Ar atmosphere. A distinct pinning–depinning behavior was observed during the evaporation-coupled wetting process. The underlying mechanism for this behavior was expatiated from the viewpoints of energetics and geometries at the triple junction.