EFFECTS OF ALKALINE EARTH METAL OXIDES, NICKEL OXIDE, AND COBALT OXIDE ON THE VISCOSITY OF LEAD-METASILICATE MELTS.

Abstract

The viscosities of melts in the PbO-CaO-SiO//2,PbO-MgO-SiO//2,PbO-BaO-SiO//2,PbO-NiO-SiO//2 and the Pbo-CoO-SiO//2 systems containing 50 mol% SiO//2 were measured in the temperature range from 950 to 1250 degree C by means of the counterbalanced sphere method. Instead of Stoke's law, Oseen's equation was applied to determine viscosities in the range from 0. 1 to 1 Pa. s under the experimental condition assuming that the Reynolds number of the flow is higher than 0. 1. The structural changes of the silicate anions in these metls are estimated from the viscosity changes in the composition, and these results are combined with the previously reported experimental results on the activities of PbO in these systems in order to discuss the behavior of the basic oxides in these systems.