Measurement of surface tension of liquid metals by means of oscillating drop technique
Kirmanj AZIZ
Institute of Experimental Physics, TU Graz
14:10 - 14:50 Friday 22 May 2015 HS P3 PH02112

The oscillating drop technique is an established method for measurement of surface tension. The thermo- and metalphysics group at Graz University of technology uses the oscillating drop technique in combination with an electromagnetic levitation device to measure surface tension of liquid metals and alloys.
An electromagnetic levitation device employs an inhomogeneous radio-frequency electromagnetic field inside a levitation coil to heat and position the specimens. Induced eddy currents heat up the material into the liquid phase and exert a Lorentz force, pushing it towards regions of lower field strength. The levitating specimen is investigated by optical setups to provide a contactless measurement. A high-speed camera with up to 600 fps and a pyrometer operating at 1600 nm are used to determine the surface tension as a function of temperature.
As electromagnetic levitation is a container-less and contactless measuring method, contamination of the specimen is avoided and so investigation of even undercooled liquid metals is possible. Data for temperature dependence of surface tension of some liquid metals will be presented.