Accession Number : AD0622430

Title :   SOME STUDIES ON MONOCLINIC ZIRCONIUM DIOXIDE FROM ROOM TEMPERATURE TO 1095C.

Descriptive Note : Final rept. for Jan-31 Dec 64,

Corporate Author : OWENS-ILLINOIS TECHNICAL CENTER TOLEDO OHIO

Personal Author(s) : Lang,S. M. ; Franklin,E. W. ; Tylutki,N. J.

Report Date : JUL 1965

Pagination or Media Count : 32

Abstract : High-temperature x-ray diffractometry was used to investigate on e of the mechanisms proposed for the monoclinic-to-tetragonal transformations of ZrO2 and to demonstrate the necessity for recognizing, and eliminating or substantially reducing, the uncertainties of various experimental parameters; particularly those associated with material characterization and precision diffraction measurements. A number of previously unresolved low-angle monoclinic ZrO2 diffraction maxima are reported. It was shown that the SiO2-ZrO2 phase equilibrium diagram requires modification to account for 0.1 to 0.3 wt% of zircon as a stable impurity phase. Strain relaxations in monoclinic ZrO2 near, but below, the transformation temperature could not be detected. The diffraction data obtained were used to calculate axial expansion data between 28 and 1095C. The evaluation of the deviations between observed and calculated diffration maxima locations and assignment of reliable test temperature values required precise diffraction measurements and calculation methods. The latest instrumental alignment modifications required to obtain the necessary diffraction data are reported. The method for calculating exact monoclinic system crystallographic constants values is described. (Author)

Descriptors :   (*ZIRCONIUM COMPOUNDS, DIOXIDES), (*X RAY DIFFRACTION, ZIRCONIUM COMPOUNDS), TRANSFORMATIONS, SILICON COMPOUNDS, OXIDES, CRYSTALLOGRAPHY, IMPURITIES, CRYSTAL LATTICES

Distribution Statement : APPROVED FOR PUBLIC RELEASE