Density and viscosity of the binary Zr64Ni36 liquid alloy

J. Brillo1, A. Pommrich1, S. Schneider1 and A. Meyer1

1German Aerospace Center, Institute of Materials Physics in Space, Cologne, Germany

Keywords: electrostatic levitation; density; viscosity; liquid alloy
property: density; viscosity
material: liquid Zr-Ni

The binary alloy Zr64Ni36 serves as a model system in order to study a number of phenomena occurring during the glass transition. Precise knowledge of the density and the viscosity of the liquid phase is highly important in this context. Due to the high reactivity of the alloy, however, these properties can only be measured in a contactless way. While density can be determined in an electromagnetic levitation experiment, this will not work for the viscosity under terrestrial conditions. The reason for this is the disturbing influence of strong electromagnetic field which cannot be compensated. With the development of electrostatic levitation, an additional option has now become available for the containerless measurement of density and viscosity under gravity conditions. In electrostatic levitation the sample is charged and positioned between two electrodes. It is heated and molten, using two infra red lasers. A CCD camera records a series of side view shadow images. The volume is calculated afterwards from an average of the profile lines and the density was obtained from M/V with M beeing the sample mass. In order to determine the viscosity, the P2,0 surface oscillation mode is excited by superimposing an AC voltage on the levitation field for a certain time. The viscosity is then calculated from the measured time decay, after the AC voltage has been switched off again. In this work, results for both, density and viscosity, measured in an electrostatic levitator will be presented and discussed.

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