Energy loss and x-ray analysis of major constituents in silicon oxynitride ceramics

1987 ◽  
Vol 45 ◽  
pp. 164-165
Author(s):  
W. Braue ◽  
W.M. Skiff ◽  
R.W. Carpenter ◽  
H. Ma
Keyword(s):  
Energy Loss ◽  
Bond Length ◽  
Orthorhombic Phase ◽  
Silicon Oxynitride ◽  
Minor Phase ◽  
Tetrahedral Environment ◽  
First Results ◽  
Powder Particles ◽  
Plate Morphology ◽  
A Minor

Silicon Oxynitride (Si2N2O) is an orthorhombic phase that often occurs as a minor phase In Si3N4-base structural ceramics. It is thought to form as a result of oxygen surface contamination of the constituent powder particles, usually exhibits a rod or plate morphology and may react with sintering aids or impurities in the system. The structure of Si2N2O is a network of distorted Si-centered SiN3O tetrahedra in which the tetrahedral environment of the Si is similar to its environment in Si3N4 and SiO2. The average Si-N bond length is smaller, compared to both Si3N4 allotropes, with an Si-0 bond length typical of most silicates. EELS spectra of Si3 N4, and SiO2 are well known.Here we present the first results of a high resolution EELS study to compare the energy loss core edges of Si, 0 and N in Si2N2O to the corresponding edges in Si3N4 and SiO2.

scholarly journals Ye’elimite synthesis by chemical routes and role of iron

2021 ◽  
Vol 348 ◽  
pp. 01009
Author(s):  
Fatima-Zahra Abir ◽  
Mohamed Mesnaoui ◽  
Younes Abouliatim ◽  
Lhbib Nibou ◽  
Youssef El Hafiane ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Iron Oxide ◽  
Chemical Synthesis ◽  
Carbon Footprint ◽  
Sintering Temperature ◽  
Orthorhombic Phase ◽  
Cement Industry ◽  
Minor Phase ◽  
A Minor

The cement industry has been taking significant steps for years to reduce its carbon footprint by opting for alternative less polluting materials such as sulfo-aluminous cements (CSA). These binders, compared to ordinary Portland cements (OPC), have two advantages: reduction of the CO2 emissions and energy saving because the sintering temperature of CSA cements is much lower than ordinary cement (Portland). The aim of this work is to study the effect of iron oxide on the formation of the ye'elimite phase, which represents the main phase of (CSA).This study details the protocol for the chemical synthesis of ye’elimite containing increasing amounts of iron (general formula: Ca4Al(6-2x)Fe2xSO16 with x = 0.00 to 1.13). The maximum ye’elimite content is reached at a sintering temperature of 1250°C. The presence of iron promotes the formation of cubic ye'elimite at the expense of the orthorhombic phase. The total incorporation of iron in ye’elimite structure is possible when x < 0.12. Beyond this content, the ferritic phase (CaO)2(Al2O3,Fe2O3) appears as a minor phase and its quantity becomes more important with the increase of the percentage of iron introduced in the synthesis. Finally, the electron microscopy allows to observe nanometric grains assembled in larger aggregates.

scholarly journals Tris(4-methoxyphenyl)phosphine selenide

IUCrData ◽  
2016 ◽  
Vol 1 (8) ◽  
Author(s):  
Melina Raymundo ◽  
Clifford W. Padgett ◽  
Will E. Lynch
Keyword(s):  
Bond Length ◽  
Title Compound ◽  
Phenyl Ring ◽  
Phosphine Selenide ◽  
Torsion Angles ◽  
Compound C ◽  
Tetrahedral Environment ◽  
Methoxy Groups ◽  
Phenyl Rings ◽  
Close Contacts

The title compound, C21H21O3PSe, is comprised of a P atom in a distorted tetrahedral environment, attached to the Se atom and three C atoms of the phenyl rings. The P—Se bond length is 2.1214 (12) Å. All three methoxy groups are near coplanar with their respective phenyl rings, with the angles between the phenyl ring and the C—O bond of the methoxy groups being 5.7 (2), 1.5 (4), and 5.7 (3)°. The torsion angles of the phenyl rings relative to the P=Se bond are 35.62 (10), 35.07 (13), and 44.50 (11)°. No strong intermolecular interactions were observed, but that in addition to van der Waals forces, there are C—H...π and C—H...Se close contacts.

Heterogeneous Formation of Oriented Silicon Oxynitride on α-Si3N4 Seed Crystals : Habits And Radiation Stability

1999 ◽  
Vol 5 (S2) ◽  
pp. 778-779
Author(s):  
R.W Carpenter ◽  
W Braue ◽  
M.J. Kim
Keyword(s):  
Silicon Nitride ◽  
Heterogeneous Nucleation ◽  
Radiation Stability ◽  
Silicon Oxynitride ◽  
Minor Constituent ◽  
Sintering Aids ◽  
Sintering Aid ◽  
Nucleation Sites ◽  
Heterogeneous Formation ◽  
A Minor

Lath-like silicon oxynitride crystals have often been observed in the microstructure of silicon nitride based ceramics after processing. They are usually located in glassy regions which are siliceous solidified sintering aid liquid, and usually contain a small (∼100nm) a-Si3N4 crystal. These nitride crystals are considered to be seeds, incompletely dissolved in the melt, that are heterogeneous nucleation sites for the oxynitride crystals. We present here the first observations of morphological and crystallographic habits between the seed nanocrystals and the host oxynitride laths.Fig. 1 shows a typical oxynitride lath containing a nitride seed crystal. The lath is surrounded by glass and ß-Si3N4 particles, and a small cristobalite particle (a minor constituent). This microstructure is from an Si02-Si3N4 ceramic processed with Al2O3 sintering aid. The same oxynitride lath/seed structures were observed when other sintering aids (eg. Y2O3, MgO, ZrO2) were used, so they are independent of sintering aid.

Local bond length variations in boron-doped nanocrystalline diamond measured by spatially resolved electron energy-loss spectroscopy

2013 ◽  
Vol 103 (3) ◽  
pp. 032105 ◽  
Author(s):  
Ying-Gang Lu ◽  
Stuart Turner ◽  
Johan Verbeeck ◽  
Stoffel D. Janssens ◽  
Ken Haenen ◽  
...  
Keyword(s):  
Energy Loss ◽  
Bond Length ◽  
Electron Energy ◽  
Electron Energy Loss Spectroscopy ◽  
Nanocrystalline Diamond ◽  
Spatially Resolved ◽  
Boron Doped ◽  
Electron Energy Loss

Sulfides in Leg 37 drill core from the Mid-Atlantic Ridge

1977 ◽  
Vol 14 (4) ◽  
pp. 674-683 ◽  
Author(s):  
Wallace H. MacLean
Keyword(s):  
Deep Ocean ◽  
Minor Element ◽  
Major Elements ◽  
Drill Core ◽  
Minor Phase ◽  
Basalt Glass ◽  
Mid Atlantic Ridge ◽  
A Minor ◽  
Drill Holes ◽  
Good Agreement

Sulfides in 27 samples of drill core from four Leg 37 drill holes have been studied. Pyrite is the most abundant sulfide, averaging 0.39 ± 0.51% of basalt samples. Also present in basalt are sparse (0.0001%) and small (< 8 μm) magmatic globules of finely intergrown pyrrhotite, pentlandite, and chalcopyrite-iss, as well as a few globules composed of only one of these minerals. Larger and more abundant magmatic globules are present in gabbro and peridotite; pyrite is a minor phase in these rocks.Fe, Ni. Cu. and S are the major elements, and Co a minor element in the globules. Averaged Ni/Cu ratios for globules are: 3.3 (peridotite), 1.0 (gabbro). and 0.4 (basalt), the decrease in ratio indicating less normative olivine in the respective parent magmas when the globules were formed.Sulfides in globules in peridotite, and to a lesser extent in gabbro, form distinct grains free of inclusions, and appear to have equilibrated to below 300 °C. In basalt the minerals are finely intergrown and indicate quenching above about 600 °C, with local equilibration at lower temperatures.Three analyses of sulfur in basalt glass ranged from 930 to 1160 ppm, in good agreement with other analyses of deep-ocean basalts.

Oxygen-nickel bond length in Ni(111)-p(2×2)O determined by electron-energy-loss fine-structure spectroscopy

1990 ◽  
Vol 41 (12) ◽  
pp. 8513-8515 ◽  
Author(s):  
L. S. Caputi ◽  
S. L. Jiang ◽  
A. Amoddeo ◽  
R. Tucci
Keyword(s):  
Fine Structure ◽  
Energy Loss ◽  
Bond Length ◽  
Electron Energy ◽  
Electron Energy Loss

Charging and geometric effects on conduction through Anthracene molecular junctions

2017 ◽  
Vol 06 (02) ◽  
pp. 1750013
Author(s):  
Rupan Preet Kaur ◽  
Ravinder Singh Sawhney ◽  
Derick Engles
Keyword(s):  
Bond Length ◽  
Electrical Conduction ◽  
Density Functional ◽  
Critical Role ◽  
Zero Bias ◽  
Functional Theory ◽  
Zero Bias Conductance ◽  
A Minor ◽  
Non Equilibrium Green’S Function ◽  
Geometric Effects

We studied the geometric effects on the charge transfer through the anthracenedithiol (ADT) molecular junction using density functional theory combined with the non-equilibrium Green’s function approach. Two major geometric aspects, bond length and bond angle, were moderated to optimize the electrical conduction. From the results established in this paper, we found that the electrical conduction can be tuned from 0.2 [Formula: see text] to 0.9 [Formula: see text] by varying the Au–S bond length, whereas the moderation of bonding angle assayed a minor change from 0.37 [Formula: see text] to 0.47 [Formula: see text]. We attributed this escalating zero bias conductance to the increasing charge on the terminal sulfur atom of the ADT molecule, which increased the energy of the HOMO orbital towards Fermi level and exhibited a semi-metallic behaviour. Therefore, geometry plays a critical role in deciding the charge transport through the metal/molecule interface.

scholarly journals The Precambrian geology of the Sârdloq area, South Greenland

1966 ◽  
Vol 5 ◽  
pp. 1-48
Author(s):  
B.F. Windley
Keyword(s):  
Minor Phase ◽  
Basic Dyke ◽  
Precambrian Geology ◽  
Dyke Intrusion ◽  
A Minor

The geology of the Sârdloq area is divided on a chronological basis into two plutonic periods, preceded, separated and followed by periods af basic dyke intrusion. During the Ketilidian plutonic period, veined, banded and homogeneaus gneisses were formed, which were deformed in three periods af folding. The gneisses contain relicts of earlier, 1st period basic dykes. F 1 folds are relicts within the regional gneiss foliation (SI); F 2 folds forrned under syn-migmatitic conditions, giving rise to a major synform the axis af which plunges shallowly NE or SW and F 3 folds are represented by a post-migmatisation buckling af the foliation an axes trending NW–SE but with variable plunge. Ultrabasic and basic intrusions are probably related to the 2nd period basic dykes intruded in the Kuanitic cratogenic period. During the Sanerutian plutonic period the earlier gneisses were reactivated to form a new, more homogeneaus granite, in which the Kuanitic basic dykes are preserved as undisturbed relicts. The intrusion of a swarm af basic dykes under late-plutonic conditions (3rd period) was followed by the intrusion af net-veined diorite sheets, emplacement af homogeneaus microgranite bodies and tectonic emplacement af layered ultrabasic bodies. The formation af abundant dilatational pegmatites and layered aplite-pegmatites followed by a minor phase af basic dyking ended the second plutonic period. During the Gardar period NE-SW and E-W trending dolerite dykes were intruded and followed by faulting and mylonitisation. A swarm af NW-SE trending dolerite dykes was intruded in post-Gardar time.

Warmer climate projections in CMIP6: the role of changes in the greenhouse gas concentrations from CMIP5 to CMIP6

2020 ◽  
Author(s):  
Klaus Wyser ◽  
Erik Kjellström ◽  
Torben Koenigk ◽  
Helena Martins ◽  
Ralf Döscher
Keyword(s):  
Radiative Forcing ◽  
Climate Models ◽  
Climate Impact ◽  
Earth Model ◽  
Minor Role ◽  
Climate Projections ◽  
First Results ◽  
Effective Radiative Forcing ◽  
A Minor ◽  
New Generation

&lt;p&gt;Many modelling groups have contributed with CMIP6 scenario experiments to the CMIP6 archive. The analysis of CMIP6 future projections has started and first results indicate that CMIP6 projections are warmer than their counterparts from CMIP5. To some extent this is explained with the higher climate sensitivity of many of the new generation of climate models. However, not only have models been updated since CMIP5 but also the forcings have changed from RCPs to SSPs. The new SSPs have been designed to have the same instantaneous radiative forcing at the end of the 21st century. However, we find that in the EC-Earth3 model the effective radiative forcing differs substantially when the GHG concentrations from the SSP are replaced by those from the corresponding RCP with the same nameplate RF. We estimate that for the SSP5-8.5 and SSP2-4.5 scenarios 50% or more of the stronger warming in CMIP6 than CMIP5 for the EC-Earth model can be explained by changes in GHG gas concentrations. Other changes in the forcing datasets such as aerosols only play a minor role for the additional warming. The discrepancy between RCP and SSP forcing datasets needs to be accounted for when comparing CMIP5 and CMIP6 climate projections and should be properly conveyed to the climate impact, adaptation and mitigation communities.&lt;/p&gt;

Effect of Cao from Different Sources on the Nanostructured Cordierite

2011 ◽  
Vol 364 ◽  
pp. 368-371 ◽  
Author(s):  
Ibrahim Norfadhilah ◽  
Mohamad Hasmaliza ◽  
Zainal Arifin Ahmad ◽  
J. Banjuraizah
Keyword(s):  
Xrd Analysis ◽  
Oxide Material ◽  
X Ray Diffraction ◽  
Minor Phase ◽  
Major Phase ◽  
X Ray ◽  
Pure Oxide ◽  
Crystallite Sizes ◽  
A Minor ◽  
Different Sources

Cordierite was synthesized via glass-route using mineral and pure oxide material. Kaolin, talc, dolomite, magnesia, alumina, silica, and calcium oxide were mixed and melted. CaO from mineral and pure oxide was added in order to investigate the properties of each material in cordierite system. Sample was characterized using X-ray diffraction (XRD) analysis and dilatometer testing. The result showed that when 5wt% CaO from mineral (C5 Min) was added and sintered at 900°C, α-cordierite exist as major phase and anorthite as a minor phase. While for a sample consists of 5wt% CaO from pure oxide (C5 Ox), α-cordierite was present as major phases, µ-cordierite and anorthite as minor phases. Crystallite sizes of each material were in nanorange and crystallite size of C5 Ox was less than C5 Min.

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