Solidification behavior of low and high thermal conductivity materials in a Bridgman-Stockbarger furnace

Abstract

The solid-liquid interface position and the temperature gradients in both the solid and liquid at the interface have been studied in a modified Bridgman-Stockbarger crystal growth furnace. These crystal growth factors have been studied as a function of ampoule translation rate, materials properties, and the size and temperature of a small auxillary heater placed at the edge of the furnace hot zone. It has been found that the interface position with respect to a furnace reference point is essentially constant during a run for a low thermal conductivity material whereas the interface position changes continuosly during a run with high thermal conductivity material. However, the ampoule translation rate and auxiliary heater conditions produce interface position changes in both high and low thermal conductivity materials.