Accession Number : AD0826342

Title :   DEVELOPMENT OF HYDROTHERMAL METHOD FOR GROWING SINGLE CRYSTALS OF HIGH PURITY BERYLLIUM OXIDE AND THE STUDY OF THE FEASIBILITY OF HYDROTHERMAL GROWTH OF SELECTED CRYSTALS.

Descriptive Note : Technical rept. 15 Oct 66-15 Oct 67,

Corporate Author : TEM-PRES RESEARCH INC STATE COLLEGE PA

Personal Author(s) : Hill, Vincent G. ; Harker, Robert I.

Report Date : NOV 1967

Pagination or Media Count : 118

Abstract : Beryllium oxide crystals weighing up to 1.3 grams have been grown hydrothermally with the nutrient temperature at 530 plus or minus 5C and the growth temperature at 500 plus or minus 5C. An alkali hydroxide solution of 4N-KOH and 0.06N-LiOH was used as the hydrothermal solvent. The mean growth rate parallel to the c-axis was 0.0026 inch per day, but rates of over 0.0056 inch have been measured. It is the positive pyramidal termination which is nucleated and grown on the seed. The crystals grown were characterized chiefly by x-ray diffraction and infrared spectroscopy techniques. Calcite crystals were grown hydrothermally from 4N-K2CO3 solution with the nutrient temperature at 525C and a 25C gradient to the growth zone. Single domain LiNbO3 crystals were grown hydrothermally by reacting equimolar mixtures of 3Li2O:Nb2O5-LiOH with Li2O:4Nb2O5. In the system of GeO2-H2O, the temperature of the quartz-rutile transition increases from 1007C at atmospheric pressure to 1083C at 1100 p.s.i., whereas the melting temperatures of both the quartz and rutile GeO2 polymorphs decrease with increasing pressure. A triple point exists at 1083C and 1100 p.s.i. (Author)

Descriptors :   (*BERYLLIUM OXIDES, CRYSTAL GROWTH), (*CRYSTAL GROWTH, FEASIBILITY STUDIES), SINGLE CRYSTALS, X RAY DIFFRACTION, INFRARED SPECTROSCOPY, IMPURITIES, SYMMETRY(CRYSTALLOGRAPHY), CRYSTAL STRUCTURE, CALCITE, LITHIUM COMPOUNDS, NIOBATES, GERMANIUM COMPOUNDS, OXIDES.

Subject Categories : Crystallography

Distribution Statement : APPROVED FOR PUBLIC RELEASE