Detection of first-order liquid/liquid phase transitions in yttrium oxide-aluminum oxide melts

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GREAVES, G. N., WILDING, Martin, FEARN, S., LANGSTAFF, D., KARGL, F., COX, S., VAN, Q. Vu, MAJERUS, O., BENMORE, C. J., WEBER, R., MARTIN, C. M. and HENNET, L. (2008). Detection of first-order liquid/liquid phase transitions in yttrium oxide-aluminum oxide melts. Science, 322 (5901), 566-570. [Article]

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Abstract

We combine small-angle x-ray scattering (SAXS) and wide-angle x-ray scattering (WAXS) with aerodynamic levitation techniques to study in situ phase transitions in the liquid state under contactless conditions. At very high temperatures, yttria-alumina melts show a first-order transition, previously inferred from phase separation in quenched glasses. We show how the transition coincides with a narrow and reversible maximum in SAXS indicative of liquid unmixing on the nanoscale, combined with an abrupt realignment in WAXS features related to reversible shifts in polyhedral packing on the atomic scale. We also observed a rotary action in the suspended supercooled drop driven by repetitive transitions (a polyamorphic rotor) from which the reversible changes in molar volume (1.2 ± 0.2 cubic centimeters) and entropy (19 ± 4 joules mole–1 kelvin–1) can be estimated.

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Official URL:

http://science.sciencemag.org/content/322/5901/566

Research Institute, Centre or Group - Does NOT include content added after October 2018:

Materials and Engineering Research Institute > Engineering Research

Departments - Does NOT include content added after October 2018:

Faculty of Science, Technology and Arts > Department of Engineering and Mathematics

Page Range:

566-570

Identifiers

Identification Number:

10.1126/science.1160766