start-ver=1.4 cd-journal=joma no-vol=59 cd-vols= no-issue=6 article-no= start-page=1314 end-page=1328 dt-received= dt-revised= dt-accepted= dt-pub-year=2024 dt-pub=20240310 dt-online= en-article= kn-article= en-subject= kn-subject= en-title= kn-title=Wetting property of Fe‐S melt in solid core: Implication for the core crystallization process in planetesimals en-subtitle= kn-subtitle= en-abstract= kn-abstract=In differentiated planetesimals, the liquid core starts to crystallize during secular cooling, followed by the separation of liquid–solid phases in the core. The wetting property between liquid and solid iron alloys determines whether the core melts are trapped in the solid core or they can separate from the solid core during core crystallization. In this study, we performed high-pressure experiments under the conditions of the interior of small bodies (0.5–3.0 GPa) to study the wetting property (dihedral angle) between solid Fe and liquid Fe-S as a function of pressure and duration. The measured dihedral angles are approximately constant after 2 h and decrease with increasing pressure. The dihedral angles range from 30° to 48°, which are below the percolation threshold of 60° at 0.5–3.0 GPa. The oxygen content in the melt decreases with increasing pressure and there are strong positive correlations between the S + O or O content and the dihedral angle. Therefore, the change in the dihedral angle is likely controlled by the O content of the Fe-S melt, and the dihedral angle tends to decrease with decreasing O content in the Fe-S melt. Consequently, the Fe-S melt can form interconnected networks in the solid core. In the obtained range of the dihedral angle, a certain amount of the Fe-S melt can stably coexist with solid Fe, which would correspond to the “trapped melt” in iron meteorites. Excess amounts of the melt would migrate from the solid core over a long period of core crystallization in planetesimals. en-copyright= kn-copyright= en-aut-name=MatsubaraShiori en-aut-sei=Matsubara en-aut-mei=Shiori kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=1 ORCID= en-aut-name=TerasakiHidenori en-aut-sei=Terasaki en-aut-mei=Hidenori kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=2 ORCID= en-aut-name=YoshinoTakashi en-aut-sei=Yoshino en-aut-mei=Takashi kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=3 ORCID= en-aut-name=UrakawaSatoru en-aut-sei=Urakawa en-aut-mei=Satoru kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=4 ORCID= en-aut-name=YumitoriDaisuke en-aut-sei=Yumitori en-aut-mei=Daisuke kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=5 ORCID= affil-num=1 en-affil=Department of Earth Sciences, Graduate School of Science and Technology, Okayama University kn-affil= affil-num=2 en-affil=Department of Earth Sciences, Graduate School of Science and Technology, Okayama University kn-affil= affil-num=3 en-affil=Institute for Planetary Materials, Okayama University kn-affil= affil-num=4 en-affil=Department of Earth Sciences, Graduate School of Science and Technology, Okayama University kn-affil= affil-num=5 en-affil=Department of Earth Sciences, Graduate School of Science and Technology, Okayama University kn-affil= END start-ver=1.4 cd-journal=joma no-vol=50 cd-vols= no-issue=3 article-no= start-page=19 end-page= dt-received= dt-revised= dt-accepted= dt-pub-year=2023 dt-pub=20230701 dt-online= en-article= kn-article= en-subject= kn-subject= en-title= kn-title=Sound velocity and elastic properties of Fe–Ni–S–Si liquid: the effects of pressure and multiple light elements en-subtitle= kn-subtitle= en-abstract= kn-abstract=Fe–Ni–S–Si alloy is considered to be one of the plausible candidates of Mercury core material. Elastic properties of Fe–Ni–S–Si liquid are important to reveal the density profile of the Mercury core. In this study, we measured the P-wave velocity (VP) of Fe–Ni–S–Si (Fe73Ni10S10Si7, Fe72Ni10S5Si13, and Fe67Ni10S10Si13) liquids up to 17 GPa and 2000 K to study the effects of pressure, temperature, and multiple light elements (S and Si) on the VP and elastic properties.
The VP of Fe–Ni–S–Si liquids are less sensitive to temperature. The effect of pressure on the VP are close to that of liquid Fe and smaller than those of Fe–Ni–S and Fe–Ni–Si liquids. Obtained elastic properties are KS0 = 99.1(9.4) GPa, KS’ = 3.8(0.1) and ρ0 =6.48 g/cm3 for S-rich Fe73Ni10S10Si7 liquid and KS0 = 112.1(1.5) GPa, KS’ = 4.0(0.1) and ρ0=6.64 g/cm3 for Si-rich Fe72Ni10S5Si13 liquid. The VP of Fe–Ni–S–Si liquids locate in between those of Fe–Ni–S and Fe–Ni–Si liquids. This suggests that the effect of multiple light element (S and Si) on the VP is suppressed and cancel out the effects of single light elements (S and Si) on the VP. The effect of composition on the EOS in the Fe–Ni–S–Si system is indispensable to estimate the core composition combined with the geodesy data of upcoming Mercury mission. en-copyright= kn-copyright= en-aut-name=YamadaIori en-aut-sei=Yamada en-aut-mei=Iori kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=1 ORCID= en-aut-name=TerasakiHidenori en-aut-sei=Terasaki en-aut-mei=Hidenori kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=2 ORCID= en-aut-name=UrakawaSatoru en-aut-sei=Urakawa en-aut-mei=Satoru kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=3 ORCID= en-aut-name=KondoTadashi en-aut-sei=Kondo en-aut-mei=Tadashi kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=4 ORCID= en-aut-name=MachidaAkihiko en-aut-sei=Machida en-aut-mei=Akihiko kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=5 ORCID= en-aut-name=TangeYoshinori en-aut-sei=Tange en-aut-mei=Yoshinori kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=6 ORCID= en-aut-name=HigoYuji en-aut-sei=Higo en-aut-mei=Yuji kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=7 ORCID= affil-num=1 en-affil=Department of Earth and Space Science, Osaka University kn-affil= affil-num=2 en-affil=Department of Earth Sciences, Okayama University kn-affil= affil-num=3 en-affil=Department of Earth Sciences, Okayama University kn-affil= affil-num=4 en-affil=Department of Earth and Space Science, Osaka University kn-affil= affil-num=5 en-affil=Synchrotron Radiation Research Center, National Institutes for Quantum Science and Technology (QST) kn-affil= affil-num=6 en-affil=Japan Synchrotron Radiation Research Institute kn-affil= affil-num=7 en-affil=Japan Synchrotron Radiation Research Institute kn-affil= en-keyword=Fe alloy kn-keyword=Fe alloy en-keyword=Sound velocity kn-keyword=Sound velocity en-keyword=Liquid kn-keyword=Liquid en-keyword=Core kn-keyword=Core en-keyword=Mercury kn-keyword=Mercury en-keyword=Light element kn-keyword=Light element END start-ver=1.4 cd-journal=joma no-vol=10 cd-vols= no-issue=1 article-no= start-page=84 end-page= dt-received= dt-revised= dt-accepted= dt-pub-year=2020 dt-pub=20200120 dt-online= en-article= kn-article= en-subject= kn-subject= en-title= kn-title=X-ray and Neutron Study on the Structure of Hydrous SiO2 Glass up to 10 GPa en-subtitle= kn-subtitle= en-abstract= kn-abstract=The structure of hydrous amorphous SiO2 is fundamental in order to investigate the effects of water on the physicochemical properties of oxide glasses and magma. The hydrous SiO2 glass with 13 wt.% D2O was synthesized under high-pressure and high-temperature conditions and its structure was investigated by small angle X-ray scattering, X-ray diffraction, and neutron diffraction experiments at pressures of up to 10 GPa and room temperature. This hydrous glass is separated into two phases: a major phase rich in SiO2 and a minor phase rich in D2O molecules distributed as small domains with dimensions of less than 100 angstrom. Medium-range order of the hydrous glass shrinks compared to the anhydrous SiO2 glass by disruption of SiO4 linkage due to the formation of Si-OD deuterioxyl, while the response of its structure to pressure is almost the same as that of the anhydrous SiO2 glass. Most of D2O molecules are in the small domains and hardly penetrate into the void space in the ring consisting of SiO4 tetrahedra. en-copyright= kn-copyright= en-aut-name=UrakawaSatoru en-aut-sei=Urakawa en-aut-mei=Satoru kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=1 ORCID= en-aut-name=InoueToru en-aut-sei=Inoue en-aut-mei=Toru kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=2 ORCID= en-aut-name=HattoriTakanori en-aut-sei=Hattori en-aut-mei=Takanori kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=3 ORCID= en-aut-name=Sano-FurukawaAsami en-aut-sei=Sano-Furukawa en-aut-mei=Asami kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=4 ORCID= en-aut-name=KoharaShinji en-aut-sei=Kohara en-aut-mei=Shinji kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=5 ORCID= en-aut-name=WakabayashiDaisuke en-aut-sei=Wakabayashi en-aut-mei=Daisuke kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=6 ORCID= en-aut-name=SatoTomoko en-aut-sei=Sato en-aut-mei=Tomoko kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=7 ORCID= en-aut-name=FunamoriNobumasa en-aut-sei=Funamori en-aut-mei=Nobumasa kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=8 ORCID= en-aut-name=FunakoshiKen-ichi en-aut-sei=Funakoshi en-aut-mei=Ken-ichi kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=9 ORCID= affil-num=1 en-affil=Department of Earth Sciences, Okayama University kn-affil= affil-num=2 en-affil=Department of Earth and Planetary Systems Science, Hiroshima University kn-affil= affil-num=3 en-affil=J-PARC Center, Japan Atomic Energy Agency kn-affil= affil-num=4 en-affil=J-PARC Center, Japan Atomic Energy Agency kn-affil= affil-num=5 en-affil=Research Center for Advanced Measurement and Characterization, National Institute for Materials Science (NIMS) kn-affil= affil-num=6 en-affil=Institute of Materials Structure Science, High Energy Accelerator Research Organization (KEK), kn-affil= affil-num=7 en-affil=Department of Earth and Planetary Systems Science, Hiroshima University kn-affil= affil-num=8 en-affil=Institute of Materials Structure Science, High Energy Accelerator Research Organization (KEK) kn-affil= affil-num=9 en-affil=Neutron Science and Technology Center, Comprehensive Research Organization for Science and Society kn-affil= en-keyword=hydrous silica glass kn-keyword=hydrous silica glass en-keyword=medium-range order kn-keyword=medium-range order en-keyword=first sharp diffraction peak kn-keyword=first sharp diffraction peak en-keyword=phase separation kn-keyword=phase separation en-keyword=small angle X-ray scattering kn-keyword=small angle X-ray scattering en-keyword=X-ray diffraction kn-keyword=X-ray diffraction en-keyword=neutron diffraction kn-keyword=neutron diffraction en-keyword=high pressure kn-keyword=high pressure END