Prewetting transitions in a near-critical metallic vapor

Velocity of sound measurements at 10 MHz in near-critical liquid and vapor mercury up to supercritical temperatures and pressures of 1900 K and 1800 bars, respectively, demonstrate the existence of a wetting transition on the walls of molybdenum and niobium cells at T-W similar or equal to 1250 K, together with an associated first-order prewetting line in the dense mercury vapor that terminates at a prewetting critical point (T-c,T-pre, p(c,pre)) greater than or similar to (1860 K, 1830 bars) lying above the bulk mercury critical point at (T-c,p(c)) = (1764 K, 1670 bars).