Effect of pressure on the viscosity of liquid ZnCl2

Abstract

The effect of pressure on the viscosity of liquid ZnCl ₂ has been measured in the range 663⩽T/K⩽719 and 50⩽P/atm⩽1000,using a falling-weight viscometer with a ceramic falling weight with a diameter considerably smaller than that of the fall tube, allowing the measurement of absolute viscosity. This viscometer has an accuracy of ca. ±5%. The viscosity at 670–720 K was found to drop with pressure, to ca. 600–700 atm, and then to rise at higher pressures. The initial drop in viscosity is interpreted as due to a partial break-up of the network structure of liquid ZnCl ₂ , while the rise in viscosity at higher pressures is probably due to the effect of pressure in suppressing ionic mobility.