Accession Number : AD0809102

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 : Progress rept. no. 9, 15 Oct 66-15 Jan 67,

Corporate Author : TEM-PRES RESEARCH INC STATE COLLEGE PA

Personal Author(s) : Hill, V. G. ; Chang, L. L. Y. ; Harker, R. I.

Report Date : 31 JAN 1967

Pagination or Media Count : 36

Abstract : Spectrographic analysis of hydrothermally grown BeO crystals showed the presence of traces of Si(4+) and Mg(2+). The effects of magnesium appears to be minor, but Si(4+) may be the cause of the observed deterioration in crystal quality. The effects of different possible dopants were evaluated. Lithium resulted in deterioration of crystal quality when its concentration in the liquid was greater than 0.25 molar. LiNbO3 was synthesized hydrothermally, and its solubility in water determined to be <0.1%. The effectiveness of LiOH, NaOH, KOH, RbOH, NH4OH, H2SO4, HCl, HNO3, HF, LiCl, NH4Cl, and NH4Cl-NH4OH in increasing this solubility was evaluated. LiNbO3 was found to be unstable in the presence of these ions, and new phases appeared. The stability relationships in the system GeO2-H2O were determined to define the P-T conditions for the growth of the two polymorphs. The stability field of the rutile form increases with pressure from 1007 C at one atmosphere to 1083 C at 1100 p.s.i. That of the quartz form decreases from 1007 - 1116 C at one atmosphere to 1068 - 1081 C at 900 p.s.i., and its field disappears above 1100 p.s.i.

Descriptors :   *CRYSTALS), *SINGLE CRYSTALS), *NIOBATES), *DIOXIDES), *CRYSTALS), (*GOLD, (*BERYLLIUM COMPOUNDS, (*OXIDES, BERYLLIUM COMPOUNDS), (*CRYSTAL GROWTH, FEASIBILITY STUDIES), (*LITHIUM COMPOUNDS, (*GERMANIUM COMPOUNDS, (*SILVER, QUALITY CONTROL, SOLUTIONS(MIXTURES), X RAY DIFFRACTION, DOPING.

Subject Categories : Crystallography

Distribution Statement : APPROVED FOR PUBLIC RELEASE