Absorption and Velocity of Ultrasonic Waves in MgCl₂-KCl and CaCl₂-KCl Binary Systems

Abstract

Absorption and velocity of ultrasonic waves in molten MgCl₂-KCl and CaCl₂-KCl mixtures have been measured by using the double-transducer pulse method. The results obtained are summarized as follows:
The relation between the ultrasonic velocity and the experimental temperature can be represented by a straight line having a negative temperature gradient over the entire range of composition for these systems.
Since the temperature dependences of the volume viscosity coefficient, η_B, and the ratio of volume and shear viscosity coefficients, η_B⁄η_s, are nearly equal to the values found in the organic liquids having associated properties, it is possible to assume that the absorption in excess of Stokes’ absorption is attributed to the existence of structural relaxation caused by a time lag in structural rearrangement.
Variations of the volume viscosity coefficient, η_B, and the adiabatic compressibility, η_s, calculated from the measured sound velocity with composition can be explained by considering the change in the consitituents existing in the melt, and the present results are well supporting the presumption derived from the results of density and surface tension measurements which are reported in the previous papers.