Dynamic Viscosity of the NaF-KF-NdF(3) Molten System

The dynamic viscosity (η) of the molten system (NaF-KF)(eut)-NdF(3) containing NdF(3) in an amount from 0 to 15 mol.% was studied by rotational viscometry using a high-temperature rheometer, FRS 1600. Viscosity measurements were carried out in the temperature range from liquidus to 1153 K. The measurement procedure was tested on the (LiF-NaF-KF)(eut) melt. The choice of the parameter shear rate was carried out according to the viscosity and flow curves. Viscosity does not depend on shear rate, and therefore the investigated melts behave like Newtonian fluids, in the range of 9–19 s(−1). The experimentally obtained viscosity values for (NaF-KF)(eut)-NdF(3) melts in a wide temperature range are described by an exponential equation. In the coordinates ln(η) = f(1/T), they are straight lines; however, their temperature coefficients are noticeably different, which indicates significant impacts of composition and temperature.