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Rare earth and barium titanates are useful as ferroelectric, dielectric, and optical materials. Measurements of their thermophysical properties in the liquid state can help guide melt processing technologies for their manufacture and advance understanding of fragile liquids’ behavior and glass formation. Here, we report the density, thermal expansion, viscosity, and surface tension of molten BaTi2O5, BaTi4O9, and 83TiO2-17RE2O3 (RE¼La or Nd). Measurements were made using electrostatic levitation and droplet oscillation techniques in microgravity, which provide access to quiescent liquid droplets and deep supercooling of 510–815K below the equilibrium melting points. Densities were measured over 900–2400 K. Viscosities were similar for all four compositions, increasing from 10 mPa s near 2100K to 30 mPa s near 1750 K. Surface tensions were 450–490 dyn cm^-1 for the rare earth titanates and 383–395 dyn cm^-1 for the barium titanates; and surface tensions of all compositions had small or negligible temperature dependence over 1700–2200K. For solids recovered after melt quenching, x-ray microtomog-raphy revealed the fracture mechanics in crystalline products and minimal internal porosity in glass products, likely arising from entrapped gas bubbles. Internal microstructures were generally similar for products processed either in microgravity or in a terrestrial aerodynamic levitator.

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• In Copyright
  This article may be downloaded for personal use only. Any other use requires prior permission of the author and AIP Publishing. This article appeared in Stephen K. Wilke et al., Appl. Phys. Lett. 124, 264102 (2024) and may be found at https://doi.org/10.1063/5.0198322.

Keyword: liquid, levitation, microgravity

Date published: 2024-06-24

Publisher: AIP Publishing

Journal:

• Applied Physics Letters (ISSN: 00036951) vol. 124 issue. 26

Funding:

• National Aeronautics and Space Administration 80NSSC19K1288
• Japan Society for the Promotion of Science KAKENHI 20H05882
• Japan Society for the Promotion of Science KAKENHI 20H05878

Manuscript type: Author's version (Accepted manuscript)

MDR DOI: https://doi.org/10.48505/nims.4559

First published URL: https://doi.org/10.1063/5.0198322

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Updated at: 2024-06-28 16:30:17 +0900

Published on MDR: 2024-06-28 16:30:18 +0900