Surface Tension and Viscosity Measurements of Liquid and Undercooled Alumina by Containerless Techniques

Electrostatic levitation and multi-beam radiative heating overcame contamination and sample position instability problems associated with handling of liquid alumina. This allowed the measurements of the surface tension and viscosity in the superheated and undercooled states using the oscillation drop method. Over the 2190–2500 K interval, the surface tension of alumina was measured as σ(T)=0.64–8.2×10-5 (T-T m) (N/m), where T m, the melting temperature, is 2327 K. Similarly, on the same temperature range, the viscosity was determined as η(T)=3.2exp [43.2×103/(R T)] (mPa·s). Both sets of data agree well with the literature values.