Development of a new method to measure surface tension of molten oxides

Physical properties of molten oxides such as viscosity and surface tension are important in various fields. However, it is very difficult to measure the properties of molten oxides owing to their high melting points, high reactivity, and high vapor pressure. Hence, the physical properties of molten oxides are scarcely reported. Therefore, we developed a new method, termed the �impingement method,� for measuring the surface tension of molten oxides in a very short time, using the aerodynamic levitation technique. In this work, we developed an apparatus for measuring the surface tension of molten Al2O3 and compared the value with that of other methods, considered as reference values. Results showed that the surface tension of molten Al2O3 was approximately 0.72 N/m at around 2500 K, which is close to the reference value; moreover, the measurements could be obtained in a very short time (approximately 80 ms). Thus, it is expected that the surface tension of molten materials with high vapor pressures such as ZrO2 and UO2 can be measured using this method.