| abstract |
Alkali halide crystal is grown from a melt in a novel graphite crucible which has a surface depth region of its inside surface impregnated with glassy carbon to eliminate porosity, so that the melt does not leak through or wet the carbon. Additionally, the graphite may be coated with glassy carbon to provide a smoother surface. Also disclosed is a porous graphite crucible lined with a layer of graphitic pyrolytic carbon to prevent wetting of the surface by the melt and to permit release of the cooled crystal without remelting. |