Measurement principles for room temperature liquid and fusible metals’ surface tension

Liquid and fusible metals have garnered considerable attention in the scientific community and industry due to a fascinating combination of thermophysical properties, namely, thermal and electrical conductivity and low phase transition temperature. Above this temperature, they are essentially liquids featuring a “high” surface tension. Such metals and alloys are potent materials for welding, soldering, and thermal transport. For these applications, an accurate knowledge of the surface tension and its temperature coefficient is of utmost importance. In the past decades, several measurement methods have been adapted and improved to measure the surface tension of liquid metals. Yet, for a specific metal/alloy and temperature system, one prefers some systems over others. This review explains the main measurement principles, sheds light on the reasons for favoring some methods over others, and briefly introduces the challenges associated with liquid metal's surface tension measurements.