Study of Molten Lanthanum, Praseodymium, and Neodymium by Electrostatic Levitation

The understanding of the nature and behavior of rare earth metals in their liquid phases requires accurate values of their physical properties. However, keeping samples in their liquid phases free from contamination for time scales long enough to carry out measurements represents a formidable challenge. This is due to high reactivity and melt contamination of lanthanum, praseodymium, and neodymium with a crucible or gaseous environment. The use of a vacuum electrostatic levitator and laser heating circumvented these difficulties and permitted the determination of the density, the surface tension, and the viscosity of several rare earth metals above and below their melting temperature. In this paper, the levitator and the non-contact measurement methods are introduced and preliminary experimental data of several thermophysical properties of La, Pr, and Nd are reported over large temperature ranges.