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.

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.

Introduction

1958 ◽  
Vol 148 (932) ◽  
pp. 285-290 ◽  
Keyword(s):  
Electron Microscopy ◽  
Point Of View ◽  
Minor Role ◽  
Heritable Variation ◽  
Genetic Determination ◽  
Self Sufficiency ◽  
Points Of View ◽  
A Minor

This discussion was arranged in the belief that diverse lines of research with microorganisms had contributed materially to the solution of the role of the cytoplasm in differentiation, and that the time was ripe to review the relationships and degree of accord between at least some of these newer lines of work. The treatment is from three points of view. First, there is the morphological framework as revealed by electron microscopy. Even though the genetic functions of the structures so revealed are as yet unknown, the fine-structure of the cytoplasm must ultimately be related to the expression of genetic functions. Secondly, there is the genetic determination of cytoplasmic variations, their nature and their stability and plasticity and the interdependence of nucleus and cytoplasm. Thirdly, there is a consideration of the biochemical self-sufficiency of the cytoplasm and its stability in terms of enzymes. It has often been stated that from the point of view of heritable variation, the cytoplasm plays a minor role. However, it plays the major role in expressing the characters determined by the genes, and its history and the effect of the environment upon it are not without influence upon the characters expressed, just as the genes influence one another. Thus the action of a gene, by which it is recognized, may be expressed in some cells or tissues, but apparently not in others. By orderly control of which genes appear to act at a given time, cells may be differentiated sequentially in a tissue for specialized functions.

TEM STUDY OF NEW HIGH-Tc SUPERCONDUCTORS IN THE Bi-Sr-Ca-Cu-O SYSTEM

1988 ◽  
Vol 02 (09) ◽  
pp. 1085-1093 ◽  
Author(s):  
J.Q. LI ◽  
D.Y. YANG ◽  
F.H. LI ◽  
Z.Y. RAN ◽  
Z.X. ZHAO
Keyword(s):  
Electron Microscopy ◽  
High Resolution Electron Microscopy ◽  
Lattice Parameters ◽  
Minor Phase ◽  
High Tc Superconductors ◽  
High Tc ◽  
Superconducting Phases ◽  
Resolution Electron ◽  
A Minor ◽  
Average Structures

Electron diffraction and high resolution electron microscopy have been used to study the structure of superconducting phases in Bi-Sr-Ca-Cu-O system. The average structures of two main superconducting phases Bi 2 Sr 2 CaCu 2 O y and Bi 2 Sr 2 Ca 2 Cu 3 O y have orthorhombic cells with lattice parameters a=5.41Å, b=5.43Å, c=30.7Å and a=5.41Å, b=5.43Å, c=36.8Å respectively. Incommensurate modulations with wave vector nearly along the b* axis appear in both phases. A minor phase in this system with the same lattice parameters a and b but a smaller c(=24.6Å) has also been observed. Intergrowth of lamellae of different phases does occur in Bi-Sr-Ca-Cu-O system.

Phase stability of B2O3-added Ba2Ti9O20 ceramic: Processing effects

2003 ◽  
Vol 18 (1) ◽  
pp. 201-207 ◽  
Author(s):  
Sea-Fue Wang ◽  
Chuang-Chung Chiang ◽  
Chai-Hui Wang ◽  
Jinn P. Chu
Keyword(s):  
Phase Transformation ◽  
Phase Stability ◽  
Sintering Temperature ◽  
Host Material ◽  
Minor Amount ◽  
Reaction Products ◽  
Effective Role ◽  
Processing Effects ◽  
A Minor

Preparation of dense and phase-pure Ba2Ti9O20 is generally difficult to achieve using solid-state reaction, since there are several thermodynamically stable compounds in the vicinity of the desired composition. This study investigated the effects of B2O3 on the densification, microstructural evolution, and phase stability of Ba2Ti9O20. Samples from the host material (2BaO · 9TiO2) with and without the addition of 5 wt% B2O3 were prepared through different processing routes. For the pure host material sintered at temperatures ranging from 800 to 1100 °C, the reaction products followed the sequence of BaTi2O5 → BaTi4O9 → BaTi5O11 → Ba2Ti9O20. The phase transformation proceeded faster in the bulk compared to the free surface of the sample. BaTi5O11 and BaTi4O9 with a minor amount of Ba2Ti9O20 were found in the ground powder of ceramics sintered at 1100 °C. For the samples prepared from host material with the addition of 5 wt% B2O3, Ba2Ti9O20 started to form at temperatures as low as 800 °C. The sequence of reaction products followed Ba4Ti13O30 → BaTi4O9 → BaTi5O11 → Ba2Ti9O20. Sintering at above 1000 °C yielded pure Ba2Ti9O20 phase, suggesting the effective role of B2O3 on the phase stability of Ba2Ti9O20. It was found that precalcination of host material before the addition of B2O3 gives an additional benefit to the Ba2Ti9O20 formation. Crystallization of pure Ba2Ti9O20 phase was completed at a sintering temperature as low as 900 °C without any solid solution additive such as SnO2 or ZrO2, due to the fact that the phase transformation of the samples began with BaTi4O9 and BaTi5O11 during sintering. Also, B2O3 was found to be unstable during the high-temperature sintering at 1200 °C, and the results are discussed.

scholarly journals Analisis Petrografi Fasa Molybdenum (Mo) dari Oksida Primer Fe2O3 Deposit Bontocani dengan Teknik X-Ray Mapping dan Difraksi Sinar-X

2017 ◽  
Vol 4 (02) ◽  
pp. 134
Author(s):  
Subaer S ◽  
Nurhayati N ◽  
Nurhasmi N ◽  
Nurfadillah N
Keyword(s):  
Electron Microscopy ◽  
Xrd Analysis ◽  
Quantitative Information ◽  
Elemental Mapping ◽  
Minor Phase ◽  
X Ray ◽  
South Sulawesi ◽  
Mineral Constituent ◽  
A Minor ◽  
Scanning Electron

<p>A researh related to petrogaphy analysis of molybdenum (Mo) has been conducted. The main objective of this study is to get quantitative information about the composotion of molybdenum (Mo) as a minor phase of primer mineral Fe2O3 deposited at Bontocani, District of Bone South Sulawesi. The petrography analysis was performed on 10 samples by means of Tescan Vega3SB Scanning Electron Microscopy (SEM) coupled with Bruker X-Ray Mapping and Energy Dispersive Spectroscopy (EDS). Crystallinity level and chemical composition<br />(phase) mineral constituent were performed by using MiniFlexII X-Ray Diifraction (XRD). The petrography analysis in the form of elemental mapping show the position of Mo along with Fe, S and other elements. The XRD analysis showed that that the Mo mineral of Bontocani deposit is found in the form of pure Mo element with a concentration of 0.2 – 8.0 wt%, compound of Fe17(Mo3)0.1 and Fe2(MoO4)3 with a concentration of 2.04 wt% and 14.0 wt%.</p>

Electron Microscopy of Metal-Matrix Composites

1970 ◽  
Vol 28 ◽  
pp. 404-405
Author(s):  
A. Lawley ◽  
M. R. Pinnel ◽  
A. Pattnaik
Keyword(s):  
Electron Microscopy ◽  
Metal Matrix Composites ◽  
Metal Matrix ◽  
Critical Evaluation ◽  
Elastic Behavior ◽  
Matrix Composites ◽  
Directionally Solidified ◽  
Fracture Characteristics ◽  
Broad Program

As part of a broad program on composite materials, the role of the interface on the micromechanics of deformation of metal-matrix composites is being studied. The approach is to correlate elastic behavior, micro and macroyielding, flow, and fracture behavior with associated structural detail (dislocation substructure, fracture characteristics) and stress-state. This provides an understanding of the mode of deformation from an atomistic viewpoint; a critical evaluation can then be made of existing models of composite behavior based on continuum mechanics. This paper covers the electron microscopy (transmission, fractography, scanning microscopy) of two distinct forms of composite material: conventional fiber-reinforced (aluminum-stainless steel) and directionally solidified eutectic alloys (aluminum-copper). In the former, the interface is in the form of a compound and/or solid solution whereas in directionally solidified alloys, the interface consists of a precise crystallographic boundary between the two constituents of the eutectic.

Site of Lysosome Production During Hepatic Injury

1969 ◽  
Vol 27 ◽  
pp. 348-349
Author(s):  
Nalin J. Unakar
Keyword(s):  
Electron Microscopy ◽  
Golgi Apparatus ◽  
Mouse Liver ◽  
Hepatic Injury ◽  
Close Approximation ◽  
Experimental Conditions ◽  
Toxic Injury

The increased number of lysosomes as well as the close approximation of lysosomes to the Golgi apparatus in tissue under variety of experimental conditions is commonly observed. These observations suggest Golgi involvement in lysosomal production. The role of the Golgi apparatus in the production of lysosomes in mouse liver was studied by electron microscopy of liver following toxic injury by CCI4.

On Future Directions in Pathology

1982 ◽  
Vol 40 ◽  
pp. 274-277
Author(s):  
Benjamin F. Trump ◽  
Irene K. Berezesky ◽  
Raymond T. Jones
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Clinical Pathology ◽  
Future Directions ◽  
Diagnostic Pathology ◽  
The Past ◽  
Transmission Electron ◽  
Organ Systems ◽  
The Many

The role of electron microscopy and associated techniques is assured in diagnostic pathology. At the present time, most of the progress has been made on tissues examined by transmission electron microscopy (TEM) and correlated with light microscopy (LM) and by cytochemistry using both plastic and paraffin-embedded materials. As mentioned elsewhere in this symposium, this has revolutionized many fields of pathology including diagnostic, anatomic and clinical pathology. It began with the kidney; however, it has now been extended to most other organ systems and to tumor diagnosis in general. The results of the past few years tend to indicate the future directions and needs of this expanding field. Now, in addition to routine EM, pathologists have access to the many newly developed methods and instruments mentioned below which should aid considerably not only in diagnostic pathology but in investigative pathology as well.

Electron Microscopy of Silicon Nitride-Based Ceramics

1991 ◽  
Vol 49 ◽  
pp. 926-927
Author(s):  
Gareth Thomas
Keyword(s):  
Electron Microscopy ◽  
High Temperature ◽  
Silicon Nitride ◽  
World Wide ◽  
Sintering Temperature ◽  
Liquid Phase Sintering ◽  
High Temperature Strength ◽  
Sintering Additives ◽  
Glass Forming ◽  
Dense Product

Silicon nitride and silicon nitride based-ceramics are now well known for their potential as hightemperature structural materials, e.g. in engines. However, as is the case for many ceramics, in order to produce a dense product, sintering additives are utilized which allow liquid-phase sintering to occur; but upon cooling from the sintering temperature residual intergranular phases are formed which can be deleterious to high-temperature strength and oxidation resistance, especially if these phases are nonviscous glasses. Many oxide sintering additives have been utilized in processing attempts world-wide to produce dense creep resistant components using Si3N4 but the problem of controlling intergranular phases requires an understanding of the glass forming and subsequent glass-crystalline transformations that can occur at the grain boundaries.

Transmission Electron Microscopy studies of texture of Cr underlayer of magnetic recording hard disk

1991 ◽  
Vol 49 ◽  
pp. 580-581
Author(s):  
L. Tang ◽  
G. Thomas ◽  
M. R. Khan ◽  
S. L. Duan
Keyword(s):  
Electron Microscopy ◽  
Thin Films ◽  
Transmission Electron Microscopy ◽  
Magnetic Recording ◽  
Magnetic Thin Films ◽  
Magnetic Films ◽  
Substrate Bias ◽  
Epitaxial Relationship ◽  
Transmission Electron

Cr thin films are often used as underlayers for Co alloy magnetic thin films, such as Co1, CoNi2, and CoNiCr3, for high density longitudinal magnetic recording. It is belived that the role of the Cr underlayer is to control the growth and texture of the Co alloy magnetic thin films, and, then, to increase the in plane coercivity of the films. Although many epitaxial relationship between the Cr underlayer and the magnetic films, such as ﹛1010﹜Co/ {110﹜Cr4, ﹛2110﹜Co/ ﹛001﹜Cr5, ﹛0002﹜Co/﹛110﹜Cr6, have been suggested and appear to be related to the Cr thickness, the texture of the Cr underlayer itself is still not understood very well. In this study, the texture of a 2000 Å thick Cr underlayer on Nip/Al substrate for thin films of (Co75Ni25)1-xTix dc-sputtered with - 200 V substrate bias is investigated by electron microscopy.

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