Effects of Oxide Additions for the Density and Surface Tension of Barium Silicate Melts

Abstract

In a previous paper, studies on the effect of oxide additions for the physical properties of lead silicate melts were reported. For a better understanding of the constitution of molten silicate, the density and surface tension of molten barium silicates containing various metallic oxides as a third element have been measured in the temperature range 1300° to 1600°C. The results obtained are as follows:
(1) The molar volume resulted from the addition of mono- or di-valent metallic oxide tends to increase with increasing ionic radius of the oxide, whereas the molar volume with tri- or tetra-valent metallic oxide does not show such a tendency on the curve.
(2) The surface tension due to the addition of alkali oxides which may be completely dissociated into ions in the silicate melts increases with ion-oxygen attraction. On the contrary, the surface tension tends to decrease with increasing ion-oxygen attraction in the case of the alkaline earth oxides. At higher values of ion-oxygen attraction the surface tension decreases, indicating that those ions may form a complex anion.