The Use of Directional Freezing of the Melt for the Preparation of Large Bismuth Single Crystals

Directional freezing is used for the preparation of large single crystals of bismuth. The diameter of cylindrical crystals obtained by this technique is 75 mm and the length 180 mm; the average mosaic spread is about 10 minutes of arc. The technique described may be applied to obtain single crystals of certain other materials which increase their volume during the process of solidification.