The Levitation Melting Facility “KTS“ is a multifunctional apparatus for alloying and casting of sensitive metallic rods using a levitated melt in a cold crucible. Avoidance of contamination by non-metallic inclusions is often crucial for the production of castings and feed rods of susceptible inter-metallic compounds. These inclusions are usually oxide phases which are often formed by reactions between the metallic melt, the crucible material and/or the surrounding atmosphere. A method to prevent this contamination is the levitation melting method. Therefor, a powerful high frequency generator (40 kW to 50 kW, up to 100 kHz) induces strong eddy currents in the metallic sample and in a copper crucible. Emerging repulsive magnetic fields cause electrodynamic suspension and magnetic levitation of the sample above the crucible. While the sample material melts due to resistive heating, the crucible is actively cooled and remains at low temperatures. A fast-moving water-cooled coquille stick is used to pull casting rods out of the levitated melt into a tube recipient. Thereafter, most of the sample material is in a "shell" of its own composition and does not come into contact with the wall of the crucible. The resulting rods have diameters of 6 mm or 8 mm and a length of approx. 10 cm, depending on the used crucible.

Furthermore, the melting can be carried out under high vacuum up to 10^-5 mbar or within an inert gas atmosphere. The vacuum is generated by a pumping unit with integrated turbo-molecular pump. The alternating electromagnetic field ensures a thorough mixing of different components in the levitated melt. The cold crucible is adjustable in the z-axis relative to the coil for an easy installation and removal of the crucible. The generator and the coil have a separate cooling circuit to prevent overheating. A high-resolution CCD camera ensures the visual observation of the process, whereat the sample temperature is measured permanently with a two-color pyrometer. All system parameters are controllable via a comfortable GUI and processed by a PLC unit. The KTS device enables the user to carry out several processes like cleaning metallic precursors by casting, pre-alloy materials and to cast the final material shaped as a rod for crystal growth.