The Effects of Oxide Additions upon the Structure Sensitive Properties of Lead Silicate Melts

Abstract

In a previous paper, studies of the various physical properties of molten lead silicates were reported. Observation of the effects of the structure sensitive properties of lead silicate melts resulting from addition of various metallic oxides as a third element should be of great importance in order to understand the constitution of molten silicates. As a result of the measurements of surface tension, density, viscosity, electrical conductivity and liquidus temperature, a linear relationship was found between these physical quantities and the radius of the added metallic ion or rather ionic potential Z⁄(r+r₀)² (where Z is valency of metallic ion, r and r₀ are radii of metallic and oxygen ions respectively). From the measurements of a freezing point depression of a compound of PbO·SiO₂, the heat of fusion was calculated to be about 5,000 cal per mole.