Viscosity measurement with an improved torsion pendulum method

In this paper, we report an improved torsion pendulum method for the viscosity measurement on molten K2O-Nb2O5 system and BaB2O4 melts, with and without flux, at high temperature in air ambient atmosphere. In K2O-Nb2O5 molten system, the viscosity shows time-dependence, indicating that the annealing process of the liquid is useful for crystal growth from the liquid. The viscosity of BaB2O4 melt has a different property between the normal and supercooling region. For the purpose of comparison, the Viscous property of fluid Hg from the reference from the normal to expanded region has been discussed. The improved torsion pendulum method shows high potential to the study of the relationship between the viscosity and composition, atmosphere, temperature and history of a liquid. (C) 1999 Elsevier Science B.V. All rights reserved.