Surface tension and viscosity of liquid and undercooled tantalum measured by a containerless method

Electrostatic levitation and multibeam radiative heating overcame contamination and sample position stability problems associated with handling of liquid tantalum. This approach allowed the measurements of the surface tension and the viscosity of the superheated and undercooled states of tantalum using the oscillation drop method. The measurements of the surface tension could be expressed as sigma(T)=2.15x10(3)-0.21(T-T-m) mN m(-1) over the 2970-3400 K interval, where T-m is the melting temperature (3290 K). The value at T-m agrees well with the scarce data appearing in the literature. Similarly, on the 3000-3400 K temperature range, the viscosity was determined as eta(T)=0.0035 exp[213.3/(RT)](mPa s). (C) 2005 American Institute of Physics.