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