APPARATUS AND METHOD FOR UNIDIRECTIONALLY SOLIDIFYING HIGH TEMPERATURE MATERIAL

摘要

An apparatus and method for unidirectionally solidifying high temperature materials comprising a graphite resistance furnace having a heat exchanger vertically positioned in the chamber thereof. The heat exchanger has inlet and exit means for the passage of an inert coolant gas therethrough. In operation, a crucible is loaded with a seed and the ceramic material to be melted and positioned in the interior of the chamber of the furnace in contact with the heat exchanger. The temperature of the melt is raised to about 50 DEG C above its melting temperature. The melt temperature is slowly decreased with a correspondingly increase in the flow of the inert coolant gas through the heat exchanger thereby unidirectionally solidifying the material to produce a single crystal.