DEVELOPMENT OF HYDROTHERMAL METHOD FOR GROWING LARGE, HIGH PURITY SINGLE CRYSTALS OF BERYLLIUM OXIDE, AND INITIATE RESEARCH ON GROWING SINGLE CRYSTALS OF 'KTN' AND CHRYSOBERYL
Abstract
Beryllium oxide crystals weighing up to 1.07 grams have been grown hydrothermally with the nutrient temperature at 535 + or - 5 C and the growth temperature at 505 + or - 5 C. Four normal potassium hydroxide was used as hydrothermal solution. Growth occurred in the vapor phase above potassium hydroxide solution. The quality of the seeds used has a major effect on the quality of the crystals grown. It is the positive pyramidal termination which is nucleated and grows on the seed. The crystals grown have been characterized by chemical, petrographic, and x-ray diffraction methods, and one crystal in particular has been shown to be of high quality. Growth rate measurements of BeO are reported. An ex-solution dome has been found in the system KNbO3-KTaO3, and the composition KtA0.65NbO.35O3(KTN), which has useful electro-optical properties at room temperatures, is metastable at temperatures below 900 + or - 10 C. The hydrothermal growth of KTN single crystals is, therefore, not feasible with the equipment currently available. Solubility determinations of chrysoberyl have been made in KOH, NAOH and water. The values obtained are far greater than those of either Al2O3 or BeO.
Document Details
- Document Type
- Technical Report
- Publication Date
- Oct 01, 1966
- Accession Number
- AD0803070
Entities
People
- R. I. Harker
- V. H. Hill