Japan Geoscience Union Meeting 2019

Presentation information

[J] Oral

S (Solid Earth Sciences ) » S-MP Mineralogy & Petrology

[S-MP33] Physics and Chemistry of Minerals

Wed. May 29, 2019 1:45 PM - 3:15 PM A07 (TOKYO BAY MAKUHARI HALL)

convener:Seiji Kamada(Frontier Research Institute for Interdisciplinary Sciences, Tohoku University), Masahiro KAYAMA(Department of Earth and Planetary Material Sciences, Faculty of Science, Tohoku University), Chairperson:Fumiya Noritake(Materials Science, Faculty of Engineering, Graduate Faculty of Interdisciplinary Research, UNIVERSITY OF YAMANASHI), Seiji Kamada(FRIS, Tohoku Univ.)

2:30 PM - 2:45 PM

[SMP33-14] Density measurement of liquid gallium using externally heated diamond anvil cell

*Ryo Tsuruoka1, Hidenori Terasaki1, Seiji Kamada2, Iori Yamada1, Fumiya Maeda3, Tadashi Kondo1, Satoru Urakawa4, Naohisa Hirao5, Akihiko Machida6 (1.Department of Earth and Space Science, Graduate School of Science Osaka University, 2.Frontier Research Institute for Interdisciplinary Sciences, Tohoku University, 3.Department of Earth and Planetary Materials Science, Graduate School of Science, Tohoku University, 4.Department of Earth Science, Okayama University, 5.Japan Synchrotron Radiation Research Institute, 6.National Institutes for Quantum and Radiological Science and Technology)

Keywords:gallium, diamond anvil cell, X-ray absorption method

Density of a liquid metal at high pressure and high temperature is fundamental information to determine its equation of state (EOS). Gallium (Ga) which has a low melting temperature at ambient pressure has been reported to have complex liquid structures. The densities of Ga at high pressures have been reported based on the measurement of volume changes (Lyapin et al. 2008), that of liquid structures (Yu et al. 2012), and that of sound velocity (Ayrinhac et al. 2015). However, these densities were not consistent each other. In this study, we measured densities of liquid Ga at high pressure using an X-ray absorption method with an externally heated diamond anvil cell (EHDAC).

Ga sample and reference materials (KBr, RbBr) were loaded into each hole drilled on a pre-indented Re gasket. The reference materials were used for estimation of sample thickness and for determination of experimental pressures (Takubo et al. 2018). The Re gasket was coated with Al2O3 to avoid a reaction between the Ga sample and the gasket. High pressure was generated using a symmetric DAC with a lever-arm frame. The culet size of the diamond anvils used was 600 μm. High temperature was generated using external heaters composed of Pt-Rh wires with a ZrO2 insulator. X-ray absorption measurements were conducted with monochromatic X-ray of 30 keV at BL10XU and BL22XU beamlines in SPring-8. Intensities of incident and transmitted X-rays were detected using a photo-diode or ion chambers. Experimental pressures were determined based on EOSs of KBr and RbBr using their volumes from XRD patterns collected using a flat panel detector.

The densities of liquid Ga were measured up to 9.4 GPa and 500 K. The densities of liquid Ga obtained at 4–9 GPa range 6.53(7)–7.25(14) g/cm3. The measured density at 4 GPa is consistent with the density calculated from sound velocity data reported by Ayrinhac et al. (2015).