Estimation of Surface Tension of Molten Silicon Using a Dynamic Hanging Drop

A new method to determine the surface tension of high-temperature liquids was developed using the rotation of a hanging drop. The measurement of surface tension of silicon melt was performed by observing the oscillation of a silicon droplet hanging from a SiC-coated carbon rod. The oscillation of the liquid drop was induced by a sudden high rotation speed above 570 rpm. The surface tension of molten silicon was estimated as 0.819 N/m at the melting point of 1415° C and its temperature coefficient was -0.308×10 -3 N/mK. We concluded that the dynamic hanging drop method could be used to measure the surface tension of high-temperature liquids.