Wettability of Lithium by Liquid Sodium, Potassium and Rubidium

The wettability of the lithium surface by liquid alkali metals Na, K and Rb is investigated for the first time by the sessile drop method in an all-soldered instrument under conditions of a high vacuum. The presence of the temperature threshold of wetting is found in Li–Na and Li–K systems at temperatures of 325°C and 160°C, respectively. A conclusion is drawn that an abrupt decrease in wetting angles in the investigated systems is associated with a marked decrease in the interfacial tension at lithium-lithium, lithium-potassium, and lithium--rubidium interfaces owing to the beginning of a noticeable mutual solubility of the components at relatively high temperatures.