Accession Number : AD0264974

Title :   AN INVESTIGATION OF THE THEORETICAL AND PRACTICAL ASPECTS OF THE THERMAL EXPANSION OF CERAMIC MATERIALS

Corporate Author : CORNELL AERONAUTICAL LAB INC BUFFALO N Y

Personal Author(s) : BROWN,W. RICHARD ; KIRCHNER,HENRY P.

Report Date : JUL 1961

Pagination or Media Count : 1

Abstract : The thermal expansion coefficients of 4 members of the homologous series of cubic rare earth oxides were measured, and plotted against the openness ratios and the molar volumes calculated for each oxide. Thermal expansion coefficient appears to increase with decreasing openness ratio or molar volume in going from Sc2O3 to the true ra e earth oxides, but within the sub-series of true rare earth oxides (Sm2O3 to Lu203), the expansion coefficient appears to be nearly constant. Other homologous series might show a similar two-part behavior. Procedures used in estimating the precision and accuracy of expansion coefficient determination by x-ray diffraction were discussed. With Cu radiation, the estimated accuracy for most of the materials of interest is + or - 1.3 x 10 to the -7th power/degree C or less, over the range 25 to 1000 C. With Cr radiation, the estimated accuracy is + or - 1.4 x 10 to the -7th power/degree C, over the range 25 to 1200 C, and + or -1.7 x 10 to the -7th power/degree C or less, over the range 25 to 1000 C. (Author)

Descriptors :   *CERAMIC MATERIALS, *THERMAL EXPANSION, CRYSTAL LATTICES, CRYSTAL STRUCTURE, DYSPROSIUM, ERBIUM, MATHEMATICAL PREDICTION, MEASUREMENT, MOLECULAR STRUCTURE, OXIDES, RARE EARTH ELEMENTS, SCANDIUM, SILVER, TRANSITION METALS, X RAY DIFFRACTION, YTTRIUM COMPOUNDS

Distribution Statement : APPROVED FOR PUBLIC RELEASE