scholarly journals LiCrO2 Under Pressure: In-Situ Structural and Vibrational Studies

Crystals ◽  
2018 ◽  
Vol 9 (1) ◽  
pp. 2 ◽  
Author(s):  
Alka Garg ◽  
Daniel Errandonea ◽  
Julio Pellicer-Porres ◽  
Domingo Martinez-Garcia ◽  
Swayam Kesari ◽  
...  
Keyword(s):  
Research Work ◽  
X Ray Diffraction ◽  
X Ray ◽  
Pressure Coefficients ◽  
Vibrational Studies ◽  
Diffraction Patterns ◽  
The Stability ◽  
Murnaghan Equation ◽  
Related Compounds

The high-pressure behaviour of LiCrO2, a compound isostructural to the battery compound LiCoO2, has been investigated by synchrotron-based angle-dispersive X-ray powder diffraction, Raman spectroscopy, and resistance measurements up to 41, 30, and 10 Gpa, respectively. The stability of the layered structured compound on a triangular lattice with R-3m space group is confirmed in all three measurements up to the highest pressure reached. The dependence of lattice parameters and unit-cell volume with pressure has been determined from the structural refinements of X-ray diffraction patterns that are used to extract the axial compressibilities and bulk modulus by means of Birch–Murnaghan equation-of-state fits. The pressure coefficients for the two Raman-active modes, A1g and Eg, and their mode-Grüneisen parameters are reported. The electrical resistance measurements indicate that pressure has little influence in the resistivity up to 10 GPa. The obtained results for the vibrational and structural properties of LiCrO2 under pressure are in line with the published results of the similar studies on the related compounds. Research work reported in this article contributes significantly to enhance the understanding on the structural and mechanical properties of LiCrO2 and related lithium compounds.

scholarly journals High-Pressure Raman Spectroscopy and X-ray Diffraction Study on Scottyite, BaCu2Si2O7

Minerals ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 608
Author(s):  
Pei-Lun Lee ◽  
Eugene Huang ◽  
Jennifer Kung
Keyword(s):  
High Pressure ◽  
Vibration Modes ◽  
X Ray Diffraction ◽  
X Ray ◽  
Raman Spectroscopic ◽  
Diamond Anvil ◽  
Compression Data ◽  
Diffraction Patterns ◽  
Murnaghan Equation

In situ high-pressure synchrotron X-ray diffraction and Raman spectroscopic experiments of scottyite, BaCu2Si2O7, were carried out in a diamond anvil cell up to 21 GPa at room temperature. X-ray diffraction patterns reveal four new peaks near 3.5, 3.1, 2.6 and 2.2 Å above 8 GPa, while some peaks of the original phase disappear above 10 GPa. In the Raman experiment, we observed two discontinuities in dν/dP, the slopes of Raman wavenumber (ν) of some vibration modes versus pressure (P), at approximately 8 and 12 GPa, indicating that the Si-O symmetrical and asymmetrical vibration modes change with pressure. Fitting the compression data to Birch–Murnaghan equation yields a bulk modulus of 102 ± 5 GPa for scottyite, assuming Ko′ is four. Scottyite shows anisotropic compressibility along three crystallographic axes, among which c-axis was the most compressible axis, b-axis was the last and a-axis was similar to the c-axis on the compression. Both X-ray and Raman spectroscopic data provide evidences that scottyite undergoes a reversible phase transformation at 8 GPa.

scholarly journals Compressional behavior of strontianite SrCO3 by synchrotron X-ray radiation diffraction: effects of pressure transmitting media

2020 ◽  
Vol 48 (5-6) ◽  
pp. 455-467
Author(s):  
BO ZHANG ◽  
SHIJIE HUANG ◽  
WEI CHEN ◽  
BO LI ◽  
ZHILIN YE ◽  
...  
Keyword(s):  
Lattice Parameter ◽  
X Ray Diffraction ◽  
Pressure Derivative ◽  
X Ray ◽  
Diamond Anvil ◽  
Pressure Unit ◽  
Diffraction Patterns ◽  
Diffraction Effects ◽  
Murnaghan Equation

The compressional behavior of strontianite SrCO3 was investigated at ambient temperature and high pressure, using a diamond anvil cell (DAC) with Ne as a pressure transmitting medium. X-ray diffraction patterns were collected to ~52 GPa using in situ angle-dispersive synchrotron-based powder X-ray diffraction (XRD). A phase transition was observed at ~20 GPa, and no indications of further transitions were detected up to ~52 GPa. The pressure-volume (P-V) data within 0.27-17.35 GPa were fitted to a third-order Birch-Murnaghan equation of state (BM3 EoS) to obtain the elastic coefficients including zero-pressure unit-cell volume, isothermal bulk modulus and its pressure derivative: V0 = 258.4(3) Å3, KT0 = 55(2) GPa, and K'T0 = 4.3(3). The V0 and KT0 were obtained as 258.1(2) Å3 and 57.1(6) GPa, when fixed K'T0 = 4. The axial compressional behavior of strontianite was also investigated by fitting the pressure-lattice parameter data to a parameterized form of the BM3 EoS, and the compression of the a-, b-, and c-axis was strongly anisotropic, with Ka0 = 104(6), Kb0 = 52(12), and Kc0 = 31.6(5) GPa. Based on this and previous studies using different pressure transmitting media (PTM), the effects PTM on the compressional behavior of strontianite were discussed.

scholarly journals A Superhydrophobic, Antibacterial, and Durable Surface of Poplar Wood

Nanomaterials ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 1885
Author(s):  
Xinyu Wu ◽  
Feng Yang ◽  
Jian Gan ◽  
Zhangqian Kong ◽  
Yan Wu
Keyword(s):  
Stearic Acid ◽  
Antibacterial Properties ◽  
Alkali Resistance ◽  
Poplar Wood ◽  
X Ray Diffraction ◽  
X Ray ◽  
Different Temperatures ◽  
Acid And Alkali Resistance ◽  
The Stability

The silver particles were grown in situ on the surface of wood by the silver mirror method and modified with stearic acid to acquire a surface with superhydrophobic and antibacterial properties. Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), and X-ray energy spectroscopy (XPS) were used to analyze the reaction mechanism of the modification process. Scanning electron microscopy (SEM) and contact angle tests were used to characterize the wettability and surface morphology. A coating with a micro rough structure was successfully constructed by the modification of stearic acid, which imparted superhydrophobicity and antibacterial activity to poplar wood. The stability tests were performed to discuss the stability of its hydrophobic performance. The results showed that it has good mechanical properties, acid and alkali resistance, and UV stability. The durability tests demonstrated that the coating has the function of water resistance and fouling resistance and can maintain the stability of its hydrophobic properties under different temperatures of heat treatment.

scholarly journals High temperature structural study of decagonal Al-Cu-Rh quasicrystal.

2014 ◽  
Vol 70 (a1) ◽  
pp. C94-C94
Author(s):  
Pawel Kuczera ◽  
Walter Steurer
Keyword(s):  
Structural Changes ◽  
Configurational Entropy ◽  
Lattice Vibrations ◽  
X Ray Diffraction ◽  
Stabilization Mechanism ◽  
X Ray ◽  
Comparative Structure ◽  
The Stability

The structure of d(ecagonal)-Al-Cu-Rh has been studied as a function of temperature by in-situ single-crystal X-ray diffraction in order to contribute to the discussion on energy or entropy stabilization of quasicrystals (QC) [1]. The experiments were performed at 293 K, 1223 K, 1153 K, 1083 K, and 1013 K. A common subset of 1460 unique reflections was used for the comparative structure refinements at each temperature. The results obtained for the HT structure refinements of d-Al-Cu-Rh QC seem to contradict a pure phasonic-entropy-based stabilization mechanism [2] for this QC. The trends observed for the ln func(I(T1 )/I(T2 )) vs.|k⊥ |^2 plots indicate that the best on-average quasiperiodic order exists between 1083 K and 1153 K, however, what that actually means is unclear. It could indicate towards a small phasonic contribution to entropy, but such contribution is not seen in the structure refinements. A rough estimation of the hypothetic phason instability temperature shows that it would be kinetically inaccessible and thus the phase transition to a 12 Å low T structure (at ~800 K) is most likely not phason-driven. Except for the obvious increase in the amplitude of the thermal motion, no other significant structural changes, in particular no sources of additional phason-related configurational entropy, were found. All structures are refined to very similar R-values, which proves that the quality of the refinement at each temperature is the same. This suggests, that concerning the stability factors, some QCs could be similar to other HT complex intermetallic phases. The experimental results clearly show that at least the ~4 Å structure of d-Al-Cu-Rh is a HT phase therefore entropy plays an important role in its stabilisation mechanism lowering the free energy. However, the main source of this entropy is probably not related to phason flips, but rather to lattice vibrations, occupational disorder unrelated to phason flips like split positions along the periodic axis.

scholarly journals Evidence for the stability of ultrahydrous stishovite in Earth’s lower mantle

2019 ◽  
Vol 117 (1) ◽  
pp. 184-189 ◽  
Author(s):  
Yanhao Lin ◽  
Qingyang Hu ◽  
Yue Meng ◽  
Michael Walter ◽  
Ho-Kwang Mao
Keyword(s):  
Transition Zone ◽  
Lower Mantle ◽  
Water Reservoir ◽  
Weight Percent ◽  
X Ray Diffraction ◽  
X Ray ◽  
Mineral Components ◽  
The Stability ◽  
Stability Of Water

The distribution and transportation of water in Earth’s interior depends on the stability of water-bearing phases. The transition zone in Earth’s mantle is generally accepted as an important potential water reservoir because its main constituents, wadsleyite and ringwoodite, can incorporate weight percent levels of H2O in their structures at mantle temperatures. The extent to which water can be transported beyond the transition zone deeper into the mantle depends on the water carrying capacity of minerals stable in subducted lithosphere. Stishovite is one of the major mineral components in subducting oceanic crust, yet the capacity of stishovite to incorporate water beyond at lower mantle conditions remains speculative. In this study, we combine in situ laser heating with synchrotron X-ray diffraction to show that the unit cell volume of stishovite synthesized under hydrous conditions is ∼2.3 to 5.0% greater than that of anhydrous stishovite at pressures of ∼27 to 58 GPa and temperatures of 1,240 to 1,835 K. Our results indicate that stishovite, even at temperatures along a mantle geotherm, can potentially incorporate weight percent levels of H2O in its crystal structure and has the potential to be a key phase for transporting and storing water in the lower mantle.

In situ coupling of atomic force microscopy and sub-micrometer focused X-ray techniques

2014 ◽  
Vol 1712 ◽  
Author(s):  
Thomas W. Cornelius ◽  
Zhe Ren ◽  
Francesca Mastropietro ◽  
Simon Langlais ◽  
Anton Davydok ◽  
...  
Keyword(s):  
Mechanical Response ◽  
Elemental Distribution ◽  
X Ray Diffraction ◽  
X Ray ◽  
Cu Nanowires ◽  
Force Microscopy ◽  
Indentation Tests ◽  
Scanning Force ◽  
Diffraction Patterns

ABSTRACTA scanning force microscope for in situ nanofocused X-ray studies (SFINX) has been developed which can be installed on diffractometers at synchrotron beamlines allowing for the combination with various techniques such as coherent X-ray diffraction and fluorescence. The capabilities of this device are demonstrated on Cu nanowires and on Au islands grown on sapphire (0001). The sample topography, crystallinity, and elemental distribution of the same area are investigated by recording simultaneously an AFM image, a scanning X-ray diffraction map, and a fluorescence map. Additionally, the mechanical response of Au islands is studied by in situ indentation tests employing the AFM-tip and recording 2D X-ray diffraction patterns during mechanical loading.

Development of an in situ synchrotron X-ray total scattering setup under pressurized hydrogen gas

2018 ◽  
Vol 51 (3) ◽  
pp. 796-801 ◽  
Author(s):  
Kouji Sakaki ◽  
Hyunjeong Kim ◽  
Akihiko Machida ◽  
Tetsu Watanuki ◽  
Yoshinori Katayama ◽  
...  
Keyword(s):  
Pair Distribution Function ◽  
Hydrogen Gas ◽  
Ex Situ ◽  
Sample Holder ◽  
Hydrogen Storage Materials ◽  
X Ray Diffraction ◽  
Total Scattering ◽  
X Ray ◽  
Diffraction Patterns

This article describes the development of an in situ gas-loading sample holder for synchrotron X-ray total scattering experiments, particularly for hydrogen storage materials, designed to collect diffraction and pair distribution function (PDF) data under pressurized hydrogen gas. A polyimide capillary with a diameter and thickness of 1.4 and 0.06 mm, respectively, connected with commercially available Swagelok fittings was used as an in situ sample holder. Leakage tests confirmed that this sample holder allows 3 MPa of hydrogen gas pressure and 393 K to be achieved without leakage. Using the developed in situ sample holder, significant background and Bragg peaks from the sample holder were not observed in the X-ray diffraction patterns and their signal-to-noise ratios were sufficiently good. The PDF patterns showed sharp peaks in the r range up to 100 Å. The results of Rietveld and PDF refinements of Ni are consistent with those obtained using a polyimide capillary (1.0 mm diameter and 0.04 mm thickness) that has been used for ex situ experiments. In addition, in situ synchrotron X-ray total scattering experiments under pressurized hydrogen gas up to 1 MPa were successfully demonstrated for LaNi4.6Cu.

scholarly journals A Flow-Through Reaction Cell for Studying Minerals Leaching by In-Situ Synchrotron Powder X-ray Diffraction

Minerals ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 990
Author(s):  
Fatemeh Nikkhou ◽  
Fang Xia ◽  
Xizhi Yao ◽  
Idowu A. Adegoke ◽  
Qinfen Gu ◽  
...  
Keyword(s):  
Flow Rate ◽  
Pressure Leaching ◽  
X Ray Diffraction ◽  
Reaction Cell ◽  
Time Resolved ◽  
X Ray ◽  
Ore Minerals ◽  
Flow Through ◽  
Diffraction Patterns

A flow-through reaction cell has been developed for studying minerals leaching by in-situ time-resolved powder X-ray diffraction, allowing for a better understanding of the leaching mechanisms and kinetics. The cell has the capability of independent control of temperature (up to 95 °C) and flow rate (>0.5 mL min−1) for atmospheric pressure leaching. It was successfully tested at the powder diffraction beamline at the Australian Synchrotron. Galena powder was leached in a citrate solution under flow-through condition at a flow rate of 0.5 mL min−1, while diffraction patterns were collected during the entire leaching process, showing rapid galena dissolution without the formation of secondary mineral phases. The flow-through cell can be used to study leaching processes of other ore minerals.

scholarly journals In-situhigh-pressure powder X-ray diffraction study of α-zirconium phosphate

2014 ◽  
Vol 70 (3) ◽  
pp. 510-516
Author(s):  
Jennifer E. Readman ◽  
Alistair Lennie ◽  
Joseph A. Hriljac
Keyword(s):  
High Pressure ◽  
Synchrotron Radiation ◽  
Zirconium Phosphate ◽  
Water Molecules ◽  
X Ray Diffraction ◽  
X Ray ◽  
Additional Water ◽  
Diffraction Patterns ◽  
Layered Phosphate

The high-pressure structural chemistry of α-zirconium phosphate, α-Zr(HPO4)2·H2O, was studied usingin-situhigh-pressure diffraction and synchrotron radiation. The layered phosphate was studied under both hydrostatic and non-hydrostatic conditions and Rietveld refinement carried out on the resulting diffraction patterns. It was found that under hydrostatic conditions no uptake of additional water molecules from the pressure-transmitting medium occurred, contrary to what had previously been observed with some zeolite materials and a layered titanium phosphate. Under hydrostatic conditions the sample remained crystalline up to 10 GPa, but under non-hydrostatic conditions the sample amorphized between 7.3 and 9.5 GPa. The calculated bulk modulus,K0= 15.2 GPa, showed the material to be very compressible with the weak linkages in the structure of the type Zr—O—P.

Statistical measures of spottiness in diffraction rings

2013 ◽  
Vol 47 (1) ◽  
pp. 166-172 ◽  
Author(s):  
Bridget Ingham
Keyword(s):  
Carbon Dioxide ◽  
Size Distribution ◽  
Intensity Variation ◽  
Incident Beam ◽  
Mean Square ◽  
X Ray Diffraction ◽  
X Ray ◽  
Statistical Measures ◽  
Diffraction Patterns

Spotty diffraction rings arise when the size distribution of crystallites illuminated by the incident beam includes crystallites that are large compared with the size of the beam. In this article, several statistical measures are used in conjunction to quantify spottiness and relate it to a crystallite size distribution: the number of peaks, the normalized root mean square intensity variation and the fractal dimension. These are demonstrated by way of example using synchrotron X-ray diffraction patterns collected duringin situcorrosion of mild steel in carbon dioxide-saturated aqueous brine.

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