Surface Tension of High Temperature Liquids Evaluation with a Thermal Imaging Furnace

At high temperature, the reactivity of liquid metals, salts, oxides, etc. often requires a container-less approach for studying composition-sensitive thermodynamic properties, such as component activities and surface tension. This experimental challenge limits access to essential properties, and therefore our understanding of molten systems. Herein, a thermal imaging furnace (TIF) is investigated as a mean of container-less study of molten materials via the formation of pendant drops. In situ optical characterization of a liquid metal drop is proposed through the use of a conventional digital camera. We report one possible method for measuring surface tension of molten systems using this pendant drop technique in conjunction with an image analysis procedure. Liquid copper was used to evaluate the efficacy of this method. The surface tension of liquid copper was calculated to be 1.159 \(\pm \ 0.043\) N\(\text {m}^{-1}\) at \(1084\pm 20\) \(^{\circ }\mathrm {C}\), in agreement with published values.