An Examination of Surface Tension of Binary Lithium Borate Melts as a Function of Composition and Temperature

Abstract

Surface tensions of xLi2O–(1−x)B2O3 melts, where 0≤x≤0.68, have been measured systematically with a ring method from respective liquidus temperatures up to about 1450 K. For all of the investigated melts, the relationship between surface tension and temperature can be well described by quadratic polynomial functions. With increasing Li2O content, surface tension monotonously increased, whereas the temperature coefficient of surface tension increased slowly up to about x=0.1, changed sign from positive to negative at about x=0.2, and then remained negative with further increasing Li2O content. Together with the physical properties reported in our previous work, such as density, temperature coefficient of density, and volume expansion coefficient, etc., both surface tension and temperature coefficient of surface tension have been comparatively plotted as a function of Li/B molar ratio. Differentiated from the inflections of slope in the plots of physical properties vs. Li/B molar ratio, three characteristic regions have been found in the melts of this system. Within different regions, different effects of temperature and concentration on the physical properties of melts have been observed.