Hydrothermal Growth of Single Crystals.
Technical rept. 15 Oct 67-15 Sep 68,
TEM-PRES RESEARCH INC STATE COLLEGE PA
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Hydrothermal methods have been found feasible for the growth of single crystals of beryllium oxide, ruby and calcite. The study of ruby growth has been devoted to evaluating those factors which are the most significant in producing fault-free crystals. These include 1 removal from the seeds by etching all major defect areas, 2 a stable convection system, 3 growth from a solution more dilute than previously proposed, 4 avoidance of thermal shocking which can produce cracks, 5 a positioning of the seeds in the vessel far enough away from the sides and from each other to avoid the wall effect, and 6 selecting particular crystallographic orientations for the seed plates. Single crystals of beohmite A10.OH were produced which were of sufficient size for optical properties to be measured on them. The study of beryllium oxide was concentrated on methods to produce high quality seeds. The techniques explored involved 1 rocking autoclave, 2 flux transport, 3 flux evaporation and 4 spontaneous nucleation under hydrothermal conditions. The study of calcite was devoted to a determination of the solubilities in K2CO3. Solubilities ranged from essentially zero to over 25 in 2 to 6 normal solutions between 300 and 800C, and 20,000 to 60,000 p.s.i. Author