Noncontact technique for measuring surface tension and viscosity of moltenmaterials using high temperature electrostatic levitation

A new, noncontact technique is described which entails simultaneous measure ments of the surface tension and the dynamic viscosity of molten materials. In this technique, four steps were performed to achieve the results: (1) a small sample of material was levitated and melted in a high vacuum using a high temperature electrostatic levitator, (2) the resonant oscillation of the drop was induced by applying a low level ac electric field pulse at the drop of resonance frequency, (3) the transient signals which followed the pulses were recorded, and (4) both the surface tension and the viscosity we re extracted from the signal. The validity of this technique was demonstrat ed using a molten tin and a zirconium sample. In zirconium, the measurement s could be extended to undercooled states by as much as 300 K. This techniq ue may be used for both molten metallic alloys and semiconductors. (C) 1999 American Institute of Physics. [S0034-6748(99)00206-3].