A comparison between the stability fields of a Cl-rich scapolite and the end-member marialite

2019 ◽  
Vol 104 (12) ◽  
pp. 1788-1799 ◽  
Author(s):  
Kaléo M.F. Almeida ◽  
David M. Jenkins
Keyword(s):  
Molar Ratio ◽  
Stability Field ◽  
X Ray Diffraction ◽  
Intermediate Composition ◽  
High Entropy ◽  
Bulk Salinity ◽  
Compositional Changes ◽  
Small Change ◽  
The Stability ◽  
Hydrothermal Environments

Abstract Scapolites are pervasive rock-forming aluminosilicates that are found in metamorphic, igneous, and hydrothermal environments; nonetheless, the stability field of Cl-rich scapolite is not well constrained. This experimental study investigated two reactions involving Cl-rich scapolite. First, the anhydrous reaction 1 of plagioclase + halite + calcite to form scapolite [modeled as: 3 plagioclase (Ab80An20) + 0.8 NaCl + 0.2 CaCO3 = scapolite (Ma80Me20)] was investigated to determine the effect of the Ca-rich meionite (Me = Ca4Al6Si6O24CO3) component on the Na end-member marialite (Ma = Na4Al3Si9O24Cl). Second, the effect of water on this reaction was investigated using the hydrothermally equivalent reaction 2, H2O + scapolite (Ma80Me20) = 3 plagioclase (Ab80An20) + CaCO3 + liquid, where the liquid is assumed to be a saline-rich hydrous-silicate melt. Experiments were conducted with synthetic phases over the range of 500–1030 °C and 0.4–2.0 GPa. For reaction 1, intermediate composition scapolite shows a wide thermal stability and is stable relative to plagioclase + halite + calcite at temperatures above 750 °C at 0.4 GPa and 760 °C at 2.0 GPa. For reaction 2, intermediate scapolite appears to be quite tolerant of water; it forms at a minimum bulk salinity [XNaCl = molar ratio of NaCl/(NaCl+H2O)] of the brine of approximately 0.2 XNaCl at 830 and 680 °C at pressures of 2.0 and 1.5 GPa, respectively. Based on the study done by Almeida and Jenkins (2017), pure marialite is very intolerant of water when compared to intermediate composition scapolite. Compositional changes in the scapolite and plagioclase were characterized by X-ray diffraction and electron microprobe analysis and found to shift from the nominal bulk compositions to the observed compositions of Ma85Me15 for scapolite and to Ab91An09 for plagioclase. These results were used to model the phase equilibria along the marialitemeionite join in temperature-composition space. This study demonstrates that a small change in the scapolite composition from end-member marialite to Ma85Me15 expands the stability field of marialite significantly, presumably due to the high entropy of mixing in scapolite, as well as increases its tolerance to water. This supports the much more common presence of intermediate scapolites in hydrothermal settings than either end-member meionite or marialite as is widely reported in the literature.

X-ray diffraction study of decagonal Al—Co—Ni as a function of composition

2004 ◽  
Vol 219 (10) ◽  
Author(s):  
Sergiy Katrych ◽  
Walter Steurer
Keyword(s):  
Diffuse Scattering ◽  
Stability Field ◽  
Imaging Plate ◽  
Data Sets ◽  
Scanner Data ◽  
X Ray Diffraction ◽  
Stability Range ◽  
X Ray ◽  
Decagonal Phase ◽  
The Stability

AbstractThe evolution was studied of structural order/disorder phenomena across the wide stability field of the decagonal phase in the system Al—Co—Ni. Full single-crystal X-ray diffraction data sets were collected of 31 samples annealed at 900 °C. Based on reciprocal space reconstructions of the imaging-plate-scanner data, the variation in Bragg as well as in diffuse scattering is discussed in detail. The samples were also characterized metallographically, by powder X-ray diffraction, differential thermal analysis and energy-dispersive X-ray spectroscopy. The (quasi)lattice parameters vary smoothly over the stability range of decagonal Al

Evolution of Microstructures and Properties of the AlxCrCuFeNi2 High-Entropy Alloys

2013 ◽  
Vol 745-746 ◽  
pp. 706-714 ◽  
Author(s):  
Sheng Guo Ma ◽  
Zhao Di Chen ◽  
Yong Zhang
Keyword(s):  
Phase Transformation ◽  
Cast Alloy ◽  
Alloy System ◽  
Molar Ratio ◽  
High Entropy Alloys ◽  
X Ray Diffraction ◽  
X Ray ◽  
High Entropy ◽  
Heat Treated ◽  
Xrd Patterns

The microstructure and Vickers hardness of the AlxCrCuFeNi2(x=0.5, 1.0, and 2.0 in molar ratio) high-entropy alloys with as-cast and heat-treated states were investigated. X-ray diffraction (XRD) patterns suggested that for the Al0.5 alloy annealed at 900,an incomplete phase transformation from FCC to BCC occurred, while for the Al2.0 alloy as heated at 500 and 700, a converse phase transformation from BCC to FCC was obtained. Compared with the as-cast dendrites, after heat treatment, the microstructure of the alloys was obviously coarsened or spheroidized or homogenized, whereas the resultant hardness has almost not decreased even at high heating temperatures, which indicated the probability of ordering for this alloy system and thus effectively compensating the stress and structural relaxations. The Al2.0 alloy reached the maximum hardness value of 610 HV by annealing at 1100, which might be ascribed to the worm-like nanoprecipitations and the enhanced fraction of B2-ordered precipitations. By cold rolling, the Al0.5 alloy is able to reach the yield strength of 1055 MPa and the fracture strength of 1179 MPa, which was a significant improvement in comparison with the as-cast alloy.

Depletion of Manganese in the Surface Layers of Fe-Mn-Si Shape Memory Alloys by Annealing

2015 ◽  
Vol 363 ◽  
pp. 196-201
Author(s):  
Yusuke Onuki ◽  
Shun Fujieda ◽  
Kozo Shinoda ◽  
Hiroshi Ohtani ◽  
Tadakatsu Maruyama ◽  
...  
Keyword(s):  
Surface Layer ◽  
Shape Memory Alloys ◽  
Shape Memory ◽  
Face Centered Cubic ◽  
X Ray Diffraction ◽  
Surface Layers ◽  
Hexagonal Close Packed ◽  
Compositional Changes ◽  
Face Centered ◽  
The Stability

X-ray diffraction (XRD) and electron microprobe microanalysis (EPMA) were used for characterizing the structure and composition of surface layers formed on austenitic Fe-Mn-Si shape memory alloys under vacuum. The XRD results demonstrated that during annealing, face centered cubic austenite is transformed to hexagonal close packed martensite on the alloy surface. The EMPA results revealed that manganese in the surface layer was depleted during annealing. Further, this analysis determined that the thickness of the surface layer of the alloy annealed at 1173 K for 1 h was approximately 20 μm and that value is consistent with the depth detected by XRD. The compositional changes of the surface layers such as manganese depletion by annealing were discussed based on the ternary Fe-Mn-Si phase diagram. Although the formation of body centered cubic ferrite is detrimental to shape memory alloys, the amount of manganese was also observed to change during processing and strongly influence the stability of the shape memory alloys.

A Systematic Investigation of the Stability Field of Spinel-type Gallium Oxonitrides

2009 ◽  
Vol 64 (10) ◽  
pp. 1115-1126 ◽  
Author(s):  
Stefanie A. Hering ◽  
Carmen E. Zvoriste ◽  
Ralf Riedel ◽  
Isabel Kinski ◽  
Hubert Huppertz
Keyword(s):  
Initial Conditions ◽  
Spinel Phase ◽  
Temperature Stability ◽  
Systematic Investigation ◽  
Molar Ratio ◽  
Stability Field ◽  
Experimental Conditions ◽  
Spinel Type ◽  
The Stability ◽  
End Members

Over the last years, the synthesis and characterization of new spinel-type gallium oxonitrides were in the focus of several working groups. Our systematic investigation of the formation of the gallium oxonitride spinel phases was done under different experimental conditions and with various educts already used in former studies. The experiments took place under high-pressure/high-temperature conditions in a multianvil apparatus, starting from the end members wurtzite-structured GaN and β -Ga2O3. Beside the variation of the molar ratio of the educts (w-GaN:β -Ga2O3 = 9 :1 - 1: 9), different pressures (1 - 11.5 GPa), temperatures (500 - 1350 °C), and heating protocols were studied to localize the formation area of the spinel-type gallium oxonitrides. From these results, initial conditions of 2.5 - 11.5 GPa at temperatures between 1000 - 1300 ◦C can be stated as leading to the formation of cubic, spinel-type gallium oxonitride phases. The temperature stability of the gallium oxonitride spinel phase as well as new results of the transformation of β -Ga2O3 into α-Ga2O3 are reported.

Reaktive E=C(p-p)π-Systeme, XLIII [1] Darstellung und Charakterisierung P-Phosphino- oder P-Arsino-substituierter Fluorphosphaalkene des Typs R2E-P=C(F)NEt2 (R = Me, CF3, Me2N; E = P, As) / Reactive E=C(p-p)-π Systems XLIII [1] Synthesis and Characterization of P-Phosphino or P-Arsino Substituted Fluorophosphaalkenes of the Type R2E-P=C(F)NEt2 (R= Me, CF3, Me2N; E = P As)

1996 ◽  
Vol 51 (6) ◽  
pp. 778-784 ◽  
Author(s):  
Joseph Grobe ◽  
Duc Le Van ◽  
Jost Winnemöller ◽  
Bernt Krebs ◽  
Mechtild Läge
Keyword(s):  
Lone Pair ◽  
Molar Ratio ◽  
Analogous Reaction ◽  
X Ray Diffraction ◽  
X Ray ◽  
Nitrogen Lone Pair ◽  
Type Interaction ◽  
The Stability ◽  
High Yields

Abstract The easily accessible phosphaalkene HP=C(F)NEt2 (lb) reacts with halophosphanes or -arsanes R2EX (X = Cl, I) in the presence of NEt3 to give P-phosphino- or -P-arsino substituted fluorophosphaalkenes of the type RiE-P=C(F)NEti (2 - 6) in high yields (60 - 85 %) [R2E: (CF3)2P (2), Me2N(CF3)P (3), Me2P (4), (CF3)2As (5), Me2As (6)]. The analogous reaction of ib with CF3PI2 (molar ratio 1:2) unexpectedly leads to the triphosphetene Et2N - C=P-PCF3-PCF3 (7). The stability of compounds 2 - 6 as a function of R2E decreases from As to P and from CF3 to Me, respectively. Compounds 2 - 6 generally show the Z-configuration and have been characterized by thorough spectroscopic investigations (MS,IR; 1H, 19F, 11C, 31PNMR). A single crystal X-ray diffraction study of 2 proves the π-type interaction of the nitrogen lone pair with the P=C bond thus enhancing the stability of the system and the PP bond order

scholarly journals Fossil Subduction Recorded By Quartz From The Coesite Stability Field

2020 ◽  
Author(s):  
Matteo Alvaro ◽  
Mattia L. Mazzucchelli ◽  
Ross J. Angel ◽  
Mara Murri ◽  
Nicola Campomenosi ◽  
...  
Keyword(s):  
Elastic Anisotropy ◽  
Mantle Xenoliths ◽  
Stability Field ◽  
X Ray Diffraction ◽  
Perfect Agreement ◽  
Research And Innovation ◽  
Eclogite Xenolith ◽  
The Stability ◽  
Field Geology

<p>Investigation of mantle xenoliths can provide information on the architecture and evolution of subcontinental lithospheric mantle through time. These reconstructions rely also on correct estimates of the pressures and temperatures (P-T) experienced by these rocks over time. Unlike chemical geothermobarometers, elastic geobarometry does not rely on chemical equilibrium between minerals, so it has the potential to provide information on over-stepping of reaction boundaries and to identify other examples of non-equilibrium behaviour in rocks. Here we introduce a method that exploits the elastic anisotropy of minerals to determine the unique P and T of equilibration from a measurements of single-crystal mineral inclusions trapped in a crystalline host from an eclogite xenolith [1]. We apply it to perfectly preserved quartz inclusions in garnet from eclogite xenoliths in kimberlites. We show that the elastic strains of inclusions calculated from in-house Raman spectroscopy measurements of the inclusions are in perfect agreement with those determined from in-situ X-ray diffraction measurements performed both in-house and at the synchrotron. Calculations based on these measured strains demonstrate that quartz trapped in garnet can be preserved even when the rock passes into the stability field of coesite (high pressure and temperature polymorph of quartz). This supports a metamorphic origin for these xenoliths that provides constraints on mechanisms of craton accretion from a subducted crustal protolith. Furthermore, we show that some key inclusion minerals do not always indicate the P and T attained during subduction and metamorphism.</p><p> </p><p>This project has received funding from the European Research Council under the H2020 research and innovation programme (N. 714936 TRUE DEPTHS to M. Alvaro)</p><p> </p><p>[1] M Alvaro, ML Mazzucchelli, RJ Angel, M Murri, N Campomenosi, M Scambelluri, F Nestola, A Korsakov, AA Tomilenko, F Marone, M Morana (2020) Fossil subduction recorded by quartz from the coesite stability field, Geology, 48, 24-28</p>

Study on Photocatalytic Degradation Performance of Nano Carbon Load WO3 Doping TiO2 Composites

2014 ◽  
Vol 881-883 ◽  
pp. 901-904 ◽  
Author(s):  
Jing Zhang ◽  
Hui Hui Zhu ◽  
Kai Chen Lei ◽  
Heng Quan
Keyword(s):  
Photocatalytic Degradation ◽  
Sol Gel ◽  
Molar Ratio ◽  
X Ray Diffraction ◽  
Doping Amount ◽  
X Ray ◽  
Maximum Value ◽  
Uv Visible ◽  
The Stability ◽  
Carbon Load

WO3doping TiO2composites with nanocarbon are prepared by sol-gel and hydrothermal, and the composites are studied by X-ray diffraction (XRD), UV-visible light scanning. The photocatalytic degradation effects of different conditions on the direct scarlet 4BS solution has been Investigated. The results show that doped WO3does not change the main structure of TiO2, but affect its crystalline properties. When WO3doping amount is 3.0 mol%, the crystallinity of composite reaches maximum value. The introduction of nanocarbon can improve the crystallinity of composite when the molar ratio of WO3doping is 3.0%, the photocatalytic activity is the highest, nanocarbon as a carrier can increase the photocatalyst adsorption capacity to achieve the objective of improving the photocatalytic efficiency when WO3and nanocarbon doped TiO2, the stability of the composite about catalytic activity is excellent.

Fractionation of polymethylene chains: An electron crystallographic investigation

1986 ◽  
Vol 44 ◽  
pp. 794-795
Author(s):  
Douglas L. Dorset
Keyword(s):  
Cross Section ◽  
Binary Systems ◽  
Linear Chain ◽  
Pure Component ◽  
Organic Substrates ◽  
Crystallographic Investigation ◽  
X Ray Diffraction ◽  
X Ray ◽  
Molecular Sizes ◽  
The Stability

A variety of linear chain materials exist as polydisperse systems which are difficultly purified. The stability of continuous binary solid solutions assume that the Gibbs free energy of the solution is lower than that of either crystal component, a condition which includes such factors as relative molecular sizes and shapes and perhaps the symmetry of the pure component crystal structures.Although extensive studies of n-alkane miscibility have been carried out via powder X-ray diffraction of bulk samples we have begun to examine binary systems as single crystals, taking advantage of the well-known enhanced scattering cross section of matter for electrons and also the favorable projection of a paraffin crystal structure posited by epitaxial crystallization of such samples on organic substrates such as benzoic acid.

On the Properties of an Ion Conductive System Incorporated in Hybrid Films

2000 ◽  
Vol 628 ◽  
Author(s):  
G. González ◽  
P. J. Retuert ◽  
S. Fuentes
Keyword(s):  
Electrochemical Impedance ◽  
Ternary Phase Diagram ◽  
Lithium Perchlorate ◽  
Molar Ratio ◽  
Ionic Conductors ◽  
X Ray Diffraction ◽  
Poly Ethylene Oxide ◽  
Ion Conducting ◽  
Poly Ethylene ◽  
High Degree

ABSTRACTBlending the biopolymer chitosan (CHI) with poly (aminopropilsiloxane) oligomers (pAPS), and poly (ethylene oxide) (PEO) in the presence of lithium perchlorate lead to ion conducting products whose conductivity depends on the composition of the mixture. A ternary phase diagram for mixtures containing 0.2 M LiClO4 shows a zone in which the physical properties of the products - transparent, flexible, mechanically robust films - indicate a high degree of molecular compatibilization of the components. Comparison of these films with binary CHI-pAPS nanocomposites as well as the microscopic aspect, thermal behavior, and X-ray diffraction pattern of the product with the composition PEO/CHI/pAPS/LiClO4 1:0.5:0.6:0.2 molar ratio indicates that these films may be described as a layered nanocomposite. In this composite, lithium species coordinated by PEO and pAPS should be inserted into chitosan layers. Electrochemical impedance spectroscopy measurements indicate the films are pure ionic conductors with a maximal bulk conductivity of 1.7*10-5 Scm-1 at 40 °C and a sample-electrode interface capacitance of about 1.2*10-9 F.

Effect of Hydrated Metal Salts on the Coordination Product of Cobalt(II) halide and PNP Type Ligand, 2,6-bis(di-tertbutylphosphinomethyl) pyridine

2018 ◽  
Author(s):  
Tasneem Siddiquee ◽  
Abdul Goni
Keyword(s):  
Metal Salts ◽  
Molar Ratio ◽  
Pincer Complexes ◽  
Asymmetric Unit ◽  
X Ray Diffraction ◽  
Pincer Ligand ◽  
Tetrahedral Geometry ◽  
X Ray ◽  
Distorted Tetrahedral Geometry ◽  
Cobalt Center

Chemical treatment of CoX<sub>2</sub><b><sup>. </sup></b>6H<sub>2</sub>O (X = Cl, Br, I) with the potentially tridentate PNP pincer ligand 2,6-bis(di-<i>tert</i>-butylphosphinomethyl)pyridine in 1:1 molar ratio results in cobalt(II) halide-PNP pincer complexes. The effect of the hydrated metal source on molecular structure and geometry of the complexes was studied by single crystal X-ray diffraction analysis. The complexes are neutral and the cobalt center adopts a penta-coordinate system with potential atropisomerization. Within the unit cell there are two distinct molecules per asymmetric unit. One of the two phosphorus atoms in the PNP ligand was observed to be partially oxidized to phosphinoxide. Disorder in the structure reflects a mixture of square pyramidal and distorted tetrahedral geometry.

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