A conduction-radiation model for the floating-zone technique in monoellipsoidal mirror furnaces

The floating-zone technique in monoellipsoidal mirror furnaces is considere d. A conduction-radiation model is formulated to study the thermal behaviou r of cylindrical slender samples in the case where convection in the melt h as been suppressed (for example, coated samples in microgravity conditions) . The model includes the radiative exchange between the sample and the mirr or, and the temperature dependence of the physical properties of the sample . The temperature distribution along the sample and other features like the volume of melt or the shape of the solid-liquid interfaces are analyzed. A lso, some aspects of the furnace operation are simulated. The results obtai ned with the model are compared with floating-zone experiments for coated s ilicon under microgravity and for graphite under terrestrial conditions. (C ) 1999 Elsevier Science B.V. All rights reserved.