X ray diffraction with a double hot-plate laser-heated diamond cell

In this study the structural and chemical properties of barnacle shell based bioceramic materials (i.e. hydroxyapatite, whitlockite, monetite and other phases) were produced by using mechano-chemical (hot-plate) conversion method. Cleaned barnacle shells were ball milled down to <75µm in diameter. Differential thermal and gravimetric analyses (DTA/TGA) were performed to determine the exact CaCO3 content. Sample batches of 2g were prepared from the fine powders produced. For each batch, the required volume of an aqueous H3PO4 solution was calculated in order to set the stoichiometric molar ratio of Ca/P equal to 1.5 for ß-tricalcium phosphate (ß-TCP) or to 1.667 for hydroxyapatite (HA). The temperature was set to 80°C for 15 minutes to complete the process. After the titration of the equivalent amount of H3PO4 into the prepared solution, agitation was carried out on a hot-plate (i.e. mechano-chemical processing) for 8 hours. The sediments formed were dried and the resulting TCP and HA powders were calcined at 400°C and 800°C respectively. For complete characterization of the bioceramics produced, scanning electron microscopy (SEM), fourier transform infrared spectroscopy (FTIR) and x-ray diffraction (XRD) analyses were carried out. The current study proposes a simple, economic and time efficient method for nano-bioceramic production.

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Synthesis of clathrate cerium superhydride CeH9 at 80-100 GPa with atomic hydrogen sublattice

Nature Communications ◽

10.1038/s41467-019-12326-y ◽

2019 ◽

Vol 10 (1) ◽

Cited By ~ 23

Author(s):

Nilesh P. Salke ◽

M. Mahdi Davari Esfahani ◽

Youjun Zhang ◽

Ivan A. Kruglov ◽

Jianshi Zhou ◽

...

Keyword(s):

Atomic Hydrogen ◽

High Pressures ◽

Structure Stability ◽

X Ray Diffraction ◽

Detailed Chemistry ◽

X Ray ◽

3 Dimensional ◽

Diamond Anvil ◽

Laser Heated ◽

Very High

Abstract Hydrogen-rich superhydrides are believed to be very promising high-Tc superconductors. Recent experiments discovered superhydrides at very high pressures, e.g. FeH5 at 130 GPa and LaH10 at 170 GPa. With the motivation of discovering new hydrogen-rich high-Tc superconductors at lowest possible pressure, here we report the prediction and experimental synthesis of cerium superhydride CeH9 at 80–100 GPa in the laser-heated diamond anvil cell coupled with synchrotron X-ray diffraction. Ab initio calculations were carried out to evaluate the detailed chemistry of the Ce-H system and to understand the structure, stability and superconductivity of CeH9. CeH9 crystallizes in a P63/mmc clathrate structure with a very dense 3-dimensional atomic hydrogen sublattice at 100 GPa. These findings shed a significant light on the search for superhydrides in close similarity with atomic hydrogen within a feasible pressure range. Discovery of superhydride CeH9 provides a practical platform to further investigate and understand conventional superconductivity in hydrogen rich superhydrides.

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Simulations of femtosecond X-ray diffraction from unperturbed and rapidly heated single crystals

Journal of Applied Crystallography ◽

10.1107/s0021889899002861 ◽

1999 ◽

Vol 32 (4) ◽

pp. 692-703 ◽

Cited By ~ 13

Author(s):

J. S. Wark ◽

R. W. Lee

Keyword(s):

Single Crystals ◽

Time Scales ◽

X Rays ◽

Femtosecond Pulses ◽

X Ray Diffraction ◽

Similar Time ◽

Short Pulses ◽

X Ray ◽

Laser Sources ◽

Laser Heated

Simulations are presented of the dynamical diffraction of femtosecond pulses of X-rays from crystals whose structures are modified on similar time scales. Such simulations are of relevance to experiments in which short pulses of X-rays from synchrotron or laser sources are diffracted from rapidly laser-heated crystals.

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In situ synchrotron X-ray diffraction in the laser-heated diamond anvil cell: Melting phenomena and synthesis of new materials

Coordination Chemistry Reviews ◽

10.1016/j.ccr.2014.01.034 ◽

2014 ◽

Vol 277-278 ◽

pp. 15-30 ◽

Cited By ~ 25

Author(s):

Ashkan Salamat ◽

Rebecca A. Fischer ◽

Richard Briggs ◽

Malcolm I. McMahon ◽

Sylvain Petitgirard

Keyword(s):

Diamond Anvil Cell ◽

New Materials ◽

X Ray Diffraction ◽

X Ray ◽

Diamond Anvil ◽

Laser Heated

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Deep Earth mineralogy revealed by ultrahigh-pressure experiments

Mineralogical Magazine ◽

10.1180/minmag.2014.078.2.13 ◽

2014 ◽

Vol 78 (2) ◽

pp. 437-446 ◽

Cited By ~ 2

Author(s):

Kei Hirose

Keyword(s):

Phase Transition ◽

Ultrahigh Pressure ◽

X Ray Diffraction ◽

X Ray ◽

Deep Earth ◽

Diamond Anvil ◽

Lowermost Part ◽

Fe Alloys ◽

Laser Heated

AbstractUltrahigh-pressure and -temperature (P-T) experimental techniques have progressed rapidly in recent years. By combining them with X-ray diffraction measurements at synchrotron radiation facilities, it is now possible to examine deep Earth mineralogy in situ at relevant high P-T conditions in a laser-heated diamond anvil cell (DAC). The lowermost part of the mantle, known as the D″ layer, has long been enigmatic because of a number of unexplained seismological features. Nevertheless, the discovery of a phase transition from MgSiO3 perovskite to ‘post-perovskite’ above 120 GPa and 2400 K indicates that post-perovskite is a principal constituent in the lowermost mantle, which is compatible with seismic observations. The ultrahigh P-T conditions of the Earth’s core have not been accessible by static experiments, but the structure and phase transition of Fe and Fe-alloys are now being examined up to 400 GPa and 6000 K by laser-heated DAC studies.

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