Torsion Pendulum Method in Viscosity Measurement of Melts

In this paper we present the results of our preliminary study on the improvements of torsion pendulum in order to make it suitable for the viscosity measurement of melt at high temperature. The amplitude features of conventional torsion pendulum and our method have been compared at room temperature and at high temperature, respectively. The relationship between the damping factor and the kinematical viscosity is derived and discussed. The viscous properties of molten KNbO₃ and molten Li₂B₈O₁₃ at high temperatures in air are measured with this method.