Simultaneous Measurements of Density, Viscosity, and Electric Conductivity of Melts

Abstract

An apparatus is described for the simultaneous measurements of density, viscosity, and electric conductivity of ionic liquids at high temperatures. Density is simply measured by the suspension of a platinum bob in the melt contained in a platinum crucible situated inside a vertical tube furnace. The bob is suspended by a platinum wire attached to one arm of an analytical balance. Upward or downward motion of the bob in the melt is produced by changing the weights on one pan of the balance. The velocity of the bob, directly dependent on the viscosity of the melt, is calibrated against a standard liquid from 10 to 10 000 poise. By using the suspension and the crucible as the two electrodes, the apparatus becomes a conductance cell. The corrections in density measurements due to surface tension are eliminated by the use of two bobs of different dimensions but similar suspension wires. This furnishes not only duplicate viscosity results but also two cell‐constants for electric conductance. Vacuum fusion is possible in the same apparatus.