New developments in high-pressure X-ray diffraction beamline for diamond anvil cell at SPring-8

Hirao, Naohisa; Kawaguchi, Saori I.; Hirose, Kei; Shimizu, Katsuya; Ohtani, Eiji; Ohishi, Yasuo

doi:10.1063/1.5126038

Cited by 105 publications

(52 citation statements)

References 42 publications

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“…Synchrotron XRD experiments were carried out for the samples after CO 2 laser heating using beamline BL10XU at SPring-8, where monochromatic X-rays with a wavelength of 0.04150 nm were used. The beam size was estimated to be ~ 3 μm at the sample position based on the full width at half maximum of the intensity profile of the X-ray beam 36 . A flat panel detector was used to collect XRD patterns, and the exposure time was 100 s. The analysis of the obtained XRD patterns was conducted using the IPAnalyzer and PDIndexer software 37 .…”

Section: Methodsmentioning

confidence: 99%

Diamond formation from methane hydrate under the internal conditions of giant icy planets

Kadobayashi

Ohnishi

Ohfuji

et al. 2021

Sci Rep

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Hydrocarbon chemistry in the C–O–H system at high pressure and high temperature is important for modelling the internal structure and evolution of giant icy planets, such as Uranus and Neptune, as their interiors are thought to be mainly composed of water and methane. In particular, the formation of diamond from the simplest hydrocarbon, i.e., methane, under the internal conditions of these planets has been discussed for nearly 40 years. Here, we demonstrate the formation of diamond from methane hydrate up to 3800 K and 45 GPa using a CO2 laser-heated diamond anvil cell combined with synchrotron X-ray diffraction, Raman spectroscopy, and scanning electron microscopy observations. The results show that the process of dissociation and polymerisation of methane molecules to produce heavier hydrocarbons while releasing hydrogen to ultimately form diamond proceeds at milder temperatures (~ 1600 K) and pressures (13–45 GPa) in the C–O–H system than in the C–H system due to the influence of water. Our findings suggest that diamond formation can also occur in the upper parts of the icy mantles of giant icy planets.

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Section: Methodsmentioning

confidence: 99%

Diamond formation from methane hydrate under the internal conditions of giant icy planets

Kadobayashi

Ohnishi

Ohfuji

et al. 2021

Sci Rep

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“…In situ XRD experiments were conducted at the SPring‐8 synchrotron radiation facility, Japan, using a laser‐heated diamond anvil cell (LH‐DAC) (Hirao et al, 2020 ; Ohishi et al, 2008). A symmetric‐type DAC with beveled 150‐μm culet diamond anvils was used.…”

Section: Methodsmentioning

confidence: 99%

Chemical Reaction Between Metallic Iron and a Limited Water Supply Under Pressure: Implications for Water Behavior at the Core‐Mantle Boundary

Nishi

Kuwayama

Hatakeyama

et al. 2020

Geophysical Research Letters

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Water transportation to the deep lower mantle via plate subduction may induce a reaction between water and iron at the core-mantle boundary. Recent experimental studies suggest that such a reaction may generate FeO 2 H x-rich domains, which can explain the seismic structures of the ultralow velocity zone in this region. In this study, the chemical reaction between metallic iron and a limited water supply at~120 GPa was investigated using time-resolved in situ synchrotron X-ray diffraction measurements in combination with the laser-heated diamond anvil cell technique. Contrary to the results of earlier studies, the formation of FeO instead of FeO 2 H x without intermediate phases was observed. Considering the unlimited availability of iron in the core and the limited water supply resulting from mantle downflow, the FeO-rich layers consisted of Fe-bearing ferropericlase and postperovskite, which must have locally cumulated at the bottom of the mantle simultaneously with hydrogen incorporation into the core. Plain Language Summary Water strongly influences the structure, dynamics, and evolution of the deep Earth. Recent experimental studies suggest that hydrous phases play an important role as carriers of surface water to the deep mantle via the subduction of oceanic plates. Such deep-water subduction processes may allow the surface water to reach the bottom of the mantle, where the mantle minerals are in direct contact with the iron at the core. Thus, the purpose of this study was to provide understanding regarding the behavior of water when it meets iron at the core-mantle boundary. To investigate the reaction between water and iron at high pressures and temperatures, experiments were performed using in situ X-ray diffraction measurements in combination with the diamond-anvil cell technique. The results obtained confirmed the formation of FeO during the reaction. Thus, the deep water cycle may produce FeO-rich layers at the core-mantle boundary, which may explain the seismic characteristics of the bottom of the mantle and at the top of the outer core.

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“…12) High-pressure XRD experiments were conducted at room temperature using an angular dispersion method with a monochromatic synchrotron radiation X-ray source (E = 30 keV) on the BL10XU beamline at SPring-8. 13) The diffraction patterns were recorded on an image plate detector, and the 2ª-intensity patterns were obtained by integrating the recorded two-dimensional diffraction images. 14,15) The patterns were analyzed using the PDIndexer software.…”

Section: Methodsmentioning

confidence: 99%

“…The bcc phase of a ferromagnet at ambient pressure transforms to hcp at high pressure. 13) The fcc phase with a Ni content close to the bccfcc martensitic transition line, which shows an Invar effect, transforms to bcc at low temperature. 4,5) The FeNi alloy is a base material like stainless steels, and information on its physical properties and phase stability at high pressure is fundamental to the developing highperformance alloys.…”

Section: Introductionmentioning

confidence: 99%

Pressure–Composition Phase Diagram of Fe–Ni Alloy

et al. 2020

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We investigated the structural phase transitions of FeNi alloys under hydrostatic pressure conditions at 298 K by examining the X-ray diffraction patterns of polycrystalline samples with Ni contents of 5%31.6%, and pressurecomposition phase diagram was established for the pressure range of 015 GPa. The diagram comprised three structural phases: bcc, fcc, and hcp, and these all coexisted in 25% Ni at 11 GPa during compression and in 23% Ni at 7 GPa during decompression. During both processes, low-and high-pressure phases coexisted. During the pressure-induced structural transitions, significant hysteresis was also observed. The 27% Ni alloy showed the two-stage transition: bccfcchcp, and the fcc phase was quenched to ambient pressure. For the 523% Ni alloys, a bcchcp transition was observed at high pressure. As the Ni content increased, the transition pressure decreased, and the volume reduction of the bcchcp transition also decreased due to the increase in the atomic volume of the hcp phase. The transition pressure from fcc to hcp rapidly increased with the Ni content. Compression curves of 29.9% Ni and 31.6% Ni alloys exhibited an anomaly at 2.0 and 2.9 GPa, respectively, and the compression anomaly was attributed to the magnetic transition.

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New developments in high-pressure X-ray diffraction beamline for diamond anvil cell at SPring-8

Cited by 105 publications

References 42 publications

Diamond formation from methane hydrate under the internal conditions of giant icy planets

Diamond formation from methane hydrate under the internal conditions of giant icy planets

Chemical Reaction Between Metallic Iron and a Limited Water Supply Under Pressure: Implications for Water Behavior at the Core‐Mantle Boundary

Pressure–Composition Phase Diagram of Fe–Ni Alloy

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