Method and apparatus for producing single crystals of refractory material

摘要

Single crystals of uranium dioxide are produced in a longitudinal recess formed in a solid body of compressed uranium dioxide powder located in a controlled inert atmosphere by passing an electric current therethrough from cooled electrodes which close the ends of the recess until at least part of the recess wall has been brought to sublimation temperature (2500 DEG C.). The electrodes are cooled to a temperature below that of the gas in the recess and single crystals form on the electrode faces abutting the recess.