Detection of First-Order Liquid/Liquid Phase Transitions in Yttrium Oxide-Aluminum Oxide Melts

G. N. Greaves, M. C. Wilding, S. Fearn, D. Langstaff, F. Kargl, S. Cox, Q. V. Van, O. Majerus, C. J. Benmore, R. Weber, C. M. Martin, L. Hennet
2008 Science  
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
more » ... upt 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+/-0.2cm 3 ) and entropy (19+/-4 J/mol/K) can be estimated.
doi:10.1126/science.1160766 pmid:18948535 fatcat:dbio3pdyyfhylmaffafmwt63vi