Accession Number : AD0691450

Title :   INADEQUACIES OF VISCOSITY THEORIES FOR VITREOUS KNO3 - Ca(NO3)2.

Descriptive Note : Technical rept.,

Corporate Author : CATHOLIC UNIV OF AMERICA WASHINGTON D C VITREOUS STATE LAB

Personal Author(s) : Tweer,H. ; Laberge,N. ; Macedo,P. B.

Report Date : JUL 1969

Pagination or Media Count : 23

Abstract : The viscosity of 60% NKO3 - 40% Ca(NO3)2 (% mole) was measured by the beam-bending method and found to be Arrhenius with an activation energy of 138 Kcal/mole. These new data were combined with previously reported capillary and rotation data and gave a smooth plot. The complete viscosity data were used to test the best-known viscosity theories but no reasonable fit was found. As a result of this study it was found that the temperature dependence of the viscosity is not controlled by structural effects such as free volume, configuration entropy, etc., but by activation energy effects in the viscous flow process. Finally, all theories are in error in predicting that the viscosity goes to infinity (in the annealing region) much faster than the measured values indicate. (Author)

Descriptors :   (*NITRATES, *VISCOSITY), (*GLASS, VISCOSITY), CALCIUM COMPOUNDS, POTASSIUM COMPOUNDS, TRANSITION TEMPERATURE, HEAT OF ACTIVATION, CERAMIC MATERIALS

Subject Categories : Physical Chemistry
      Ceramics, Refractories and Glass

Distribution Statement : APPROVED FOR PUBLIC RELEASE