Observation of Core-shell Droplet Formation of Molten Metal and Oxide under Microgravity Conditions by Parabolic Flight Experiments

Abstract

The formation and the oscillation behavior of the core-shell droplet are important for the investigation of the interfacial tension between two different liquids by the oscillating drop technique. On the basis of the oscillating drop technique, we are trying the measurements of the interfacial tension between molten steel and oxide (smelting slag and/or welding flux) in the International Space Station (ISS). For the ISS experiments, we must confirm the formation of core-shell shape droplet by molten steels and oxides under microgravity conditions. We observed the formation of core-shell droplet of Ag-B2O3 and Fe-welding fluxes of the ilmenite type in the short-time microgravity experiments by the parabolic flight. On the other hand, for Fe-smelting slag we cannot observe the formation of the core-shell droplet. For the case of Fe-ilmenite flux, we can observe two independent peaks from FFT analysis. In the report, we describe the details of parabolic flight experiments and also discuss the conditions of interfacial tension measurements using core-shell droplet under microgravity condition.