Droplet impingement method to measure the surface tension of molten zirconium oxide

Measuring the surface tension of molten ZrO2 is critical to determine the progression of a severe accident in a nuclear power plant. However, no experimental reports have been published pertaining to the surface tension of liquid ZrO2 because of its high melting point, high reactivity, and high vapor pressure, among other factors. Thus, in this study, the surface tension of ZrO2 was measured by using the droplet impingement method, which can help determine the surface tension of molten oxides in an extremely short time. The impingement behavior could be determined to analyze the surface tension from the image. The surface tension was approximately 0.91 N/m at 2988 K, which is the melting point of ZrO2, and this value was consistent with the data estimated using the oscillation droplet method. Compared with a past report regarding the surface tension of the molten Zr-O system, the surface tension of molten Zr was noted to reduce with oxidation.