Faculty Profiles - TERASAKI Hidenori

In situ measurement of interfacial tension of Fe-S and Fe-P liquids under high pressure using X-ray radiography and tomography techniques Reviewed

H. Terasaki, S. Urakawa, K. Funakoshi, N. Nishiyama, Y. Wang, K. Nishida, T. Sakamaki, A. Suzuki, E. Ohtani

PHYSICS OF THE EARTH AND PLANETARY INTERIORS 174 ( 1-4 ) 220 - 226 2009.5

Language：English Publishing type：Research paper (scientific journal) Publisher：ELSEVIER SCIENCE BV

Interfacial tension is one of the most important properties of the liquid iron alloy that controls the core formation process in the early history of the Earth and planets. In this study, we made high-pressure X-ray radiography and micro-tomography measurements to determine the interfacial tension between liquid iron alloys and silicate melt using the sessile drop method. The measured interfacial tension of liquid Fe-S decreased significantly (802-112 mN/m) with increasing sulphur content (0-40 at%) at 1.5 GPa. In contrast, the phosphorus content of Fe had an almost negligible effect on the interfacial tension of liquid iron. These tendencies in the effects of light elements are consistent with those measured at ambient pressure. Our results suggest that the effect of sulphur content on the interfacial tension of liquid Fe-S (690 mN/m reduction with the addition of 40 at% S) is large compared with the effect of temperature (similar to 273 mN/m reduction with an increase of 200 K). The three-dimensional structure of liquid Fe-S was obtained at similar to 2 GPa and 1373-1873 K with a high-pressure tomography technique. The Fe-S droplet was quite homogeneous when evaluated in a slice of the three-dimensional image. (C) 2009 Elsevier B.V. All rights reserved.

DOI： 10.1016/j.pepi.2009.01.004

Density measurements of liquid FeS at high pressure using X-ray absorption image.

Nishida, K, Suzuki, A, Terasaki, H, Ohtani, E, Sakamaki, T, Shibazaki, Y, Hayashi, H, Funayama, M, Kikegawa, T

Photon Factory Activity Report 2007 25 198 2009.2

Percolative core formation model in planet interiors Reviewed

Hidenori Terasaki

Japanese Magazine of Mineralogical and Petrological Sciences 38 ( 1 ) 9 - 12 2009

Language：Japanese Publishing type：Research paper (scientific journal)

The percolation of liquid iron alloy through crystalline silicates potentially played an important role during core formation in planetary bodies of the early solar system. In order to test the feasibility of percolative core formation, the effects of pressure, composition and mineral assemblage on the dihedral angle between Fe-O-S liquid and mantle minerals have been investigated from 1.5 to 23.5 GPa. Texturally-equilibrated dihedral angles increase from 54 to 106° over this pressure range. The dihedral angle increases with pressure and closely related to the oxygen content of Fe-O-S phase, which decreases with increasing pressure, because oxygen reduces the interfacial energy of Fe-S melt. However, the effect of mineral assemblage on the dihedral angle seems to be negligible. Therefore, percolation is likely to have been the dominant core formation mechanism in small relatively-oxidised planetary bodies with a radius less than abogt 1300 km.

DOI： 10.2465/gkk.38.9

Scopus

Physical properties of liquid iron-alloy under high pressure: Implications to planetary core Reviewed

Hidenori Terasaki

Review of High Pressure Science and Technology/Koatsuryoku No Kagaku To Gijutsu 19 ( 2 ) 156 - 162 2009

Language：Japanese Publishing type：Research paper (scientific journal)

Physical properties of liquid iron-alloy under high pressure control the planetary core formation, evolution and its dynamics. In this review paper, high pressure behaviors of some physical properties (viscosity, wetting property and interfacial tension) are discussed and applied to the planetary core. The viscosities of Fe-S and Fe-C liquids measured using X-ray radiography falling sphere method up to 16 GPa show low viscosity values (∼10 mPa-s) and the activation volume of viscous flow is also very small (∼1.5 cm 3/mol). The influence of light elements on the viscosity and the activation volume has only a minor contribution. Dihedral angle, i.e. wetting property of Fe-S-O liquid among mantle minerals is mainly controlled by an interfacial energy of liquid iron-alloy and not by that of solid phase. The effect of light elements on interfacial tension of Fe-S and Fe-P liquids measured using sessile drop method depends on element species. Sulphur corresponds to a surface-active element. The trend observed at high pressure is quite consistent with those at ambient pressure.

DOI： 10.4131/jshpreview.19.156

Scopus

Solidus of Carbonated Peridotite and petrogenesis of Magnesio-carbonatite in the Earth’s Upper Mantle and Transition Zone Reviewed

Ghosh, S, Ohtani, E, K. Litasov, H. Terasaki

Chemical Geology 2009

In situ X-ray experiment on the structure of basaltic magma under high pressure and high temperature.

Sakamaki, T, Suzuki, A, Ohtani, E, Terasaki, H, Funakoshi, K

SPring-8 User Experiment Report No.21 (2008A) 21 2008A1118 2008.11

高温高圧Ｘ線その場観察実験による鉄－マントル鉱物間の水素分配；火星の核-マントル境界における水素挙動の解明.

Terasaki, H, Shibazaki, Y, Ohtani, E, Suzuki, A, Sakamaki, T, Ghosh, S, Nishida, K

SPring-8 User Experiment Report No.21 (2008A) 21 2008A1145 2008.11

Ｘ線吸収法によるペリドタイトマグマの密度測定.

Ohtani, E, Suzuki, A, Terasaki, H, Sakamaki, T, Urakawa, S, Katayama, Y, Hayashi, H, Nakano, Y

SPring-8 User Experiment Report No.21 (2008A) 21 2008A3722 2008.11

The effect of sulfur content on density of the liquid Fe-S at high pressure Reviewed

K. Nishida, H. Terasaki, E. Ohtani, A. Suzuki

PHYSICS AND CHEMISTRY OF MINERALS 35 ( 7 ) 417 - 423 2008.8

Language：English Publishing type：Research paper (scientific journal) Publisher：SPRINGER

The density of liquid Fe-S was measured at 4 GPa and 1,923 K using a sink/float method with a composite density marker. The density marker consisted of a Pt rod core and an Al(2)O(3) tube surrounding. The uncertainty in the density of the composite marker is much smaller than that of the composite sphere, which had been used in previous density measurements. The density of liquid Fe-S decreases nonlinearly with increasing sulfur content at 4 GPa and 1,923 K. This tendency is consistent with the results measured at ambient pressure. The molar volume of FeS calculated from the measured density gradually increases with sulfur content. The excess molar volume from ideal mixing of Fe and S at 4 GPa was negative value. The new method proposed here is applicable to the density measurement of other Fe alloys at high pressure. The tendency of the molar volume and the excess molar volume with sulfur content at ambient pressure is consistent with these at high pressure at least up to 4 GPa. The excess molar volume at high pressure is essential for estimating the amount of light elements in the outer core.

DOI： 10.1007/s00269-008-0236-4

Percolative core formation in planetesimals Reviewed

Hidenori Terasaki, Daniel J. Frost, David C. Rubie, Falko Langenhorst

EARTH AND PLANETARY SCIENCE LETTERS 273 ( 1-2 ) 132 - 137 2008.8

Language：English Publishing type：Research paper (scientific journal) Publisher：ELSEVIER SCIENCE BV

The percolation of liquid iron alloy through crystalline silicates potentially played an important role during core formation in small bodies of the early solar system, such as asteroids and planetesimals. This is because heat production by radioactive decay of Al-26 and Fe-60. which is believed to be the main heat source in early-formed small planetary bodies, will initially cause Fe-S melts to form, well before the silicates start to melt. In order to test the feasibility of percolation, the effect of pressure on the dihedral angle between Fe-O-S liquid and olivine has been investigated from 1.5 to 5.0 GPa, a pressure range that is relevant for the interiors of large asteroids. Texturally-equilibrated dihedral angles increase from 54 degrees to 98 degrees over this pressure range. The dihedral angle reaches the critical value of 60 degrees at 2-3 GPa depending on the olivine composition (Fe#). This change in dihedral angle is related to the oxygen content of Fe-O-S phase, which decreases with increasing pressure, because oxygen dissolved in the melt reduces the Fe-S melt/olivine interfacial energy. These results show that Fe-O-S liquid can form an interconnected network and percolate through silicate aggregates under conditions of high oxygen fugacity and low pressure, even when the melt fraction is small. Therefore, percolation is likely to have been the dominant core formation mechanism in small relatively-oxidised planetary bodies with a radius less than about 1300 km. (C) 2008 Elsevier B.V. All rights reserved.

DOI： 10.1016/j.epsl.2008.06.019

Phase relations of Fe-Si alloy up to core conditions: Implications for the Earth inner core Reviewed

Hidetoshi Asanuma, Eiji Ohtani, Takeshi Sakai, Hidenori Terasaki, Seiji Kamada, Naohisa Hirao, Nagayoshi Sata, Yasuo Ohishi

GEOPHYSICAL RESEARCH LETTERS 35 ( 12 ) L12307 2008.6

Language：English Publishing type：Research paper (scientific journal) Publisher：AMER GEOPHYSICAL UNION

X-ray diffraction experiments were conducted to 257 GPa and high temperature in situ on an iron-silicon alloy containing 3.4 wt% silicon, a candidate for the Earth's inner core forming material. The results revealed that fcc and hcp phases coexist up to 104 GPa. A single hcp phase is stable at higher pressures at least up to 3600 K at 242 GPa and to 2400 K at 257 GPa. Dissolution of silicon in the liquid outer core following reaction with the silicate mantle during core formation strongly suggests the existence of silicon in the solid inner core. Our results revealed that the iron-3.4 wt% silicon alloy in the inner core is likely to possess an hcp structure, which can explain the inner core anisotropy observed in seismology.

DOI： 10.1029/2008GL033863

Interfacial tension measurement of Ni-S liquid using high-pressure X-ray micro-tomography Reviewed

Hidenori Terasaki, Satoru Urakawa, Ken-ichi Funakoshi, Yanbin Wang, Yuki Shibazaki, Takeshi Sanehira, Yasuhiro Ueda, Eiji Ohtani

HIGH PRESSURE RESEARCH 28 ( 3 ) 327 - 334 2008

Language：English Publishing type：Research paper (scientific journal) Publisher：TAYLOR & FRANCIS LTD

High-pressure, high-temperature X-ray tomography experiments have been carried out using a large volume toroidal cell, which is optimized for interfacial tension measurements. A wide anvil gap, which corresponds to a field of view in the radiography imaging, was successively maintained to high pressures and temperatures using a composite plastic gasket. Obtained interfacial tensions of Ni-S liquid against Na, K-disilicate melt, were 414 and 336 mN/m at 1253 and 1293 K, respectively. Three-dimensional tomo-graphy images revealed that the sample had an irregular shape at the early stage of melting, suggesting either non-equilibrium in sample texture and force balance or partial melting of surrounding silicate. This information cannot always be obtained from two-dimensional radiographic imaging techniques. Therefore, a three-dimensional tomography measurement is appropriate for the precise interfacial measurements.

DOI： 10.1080/08957950802208902