scholarly journals Investigation of Structural Formation of Starting Composition 2245 in the Bi-Pb-Sr-Ca-Cu-O System Superconductors

2014 ◽  
Vol 2014 ◽  
pp. 1-7
Author(s):  
Ashoka Nukkanahalli Venkataswamy ◽  
George Thomas Chirayil ◽  
Srinivasan Kannaiyan
Keyword(s):  
Heat Treatment ◽  
Volume Fraction ◽  
X Ray Diffraction ◽  
Structural Formation ◽  
Major Phase ◽  
X Ray ◽  
Superconducting Volume Fraction ◽  
Superconducting Compound ◽  
First Time

Structural formation of Bi1.65Pb0.35Sr2Ca4Cu5Oy (2245 phase) superconducting compound was investigated by preparing the sample in a new matrix route. The phases formed at different intervals of heat treatment are monitored by X-ray diffraction studies. Bi-2212 phase was found to be the predominant phase till 20 hours of sintering at 850°C after which Bi-2223 phase was found to be the major phase. Traces of Ca2PbO4 were also noticed along with 2212 and 2223 phases. For the first time, the highest TC onset of 127 K with maximum superconducting volume fraction was observed for the sample sintered at 850°C for 30 hours in this preparation. Further sintering is found to deteriorate the TC onset value of the sample. There was no signature of the formation of 2234 or 2245 phase in this synthesis.

TIN ADDITION TO THE (Bi, Pb) 2223 SYSTEM

1994 ◽  
Vol 08 (19) ◽  
pp. 1175-1183 ◽  
Author(s):  
G. RAVI CHANDRA ◽  
B. GOPALA KRISHNA ◽  
S. V. SURYANARAYANA ◽  
T. S. N. MURTHY
Keyword(s):  
Heat Treatment ◽  
Magnetic Susceptibility ◽  
Electrical Resistance ◽  
Volume Fraction ◽  
Ac Magnetic Susceptibility ◽  
Superconducting Properties ◽  
X Ray Diffraction ◽  
Metallic Behavior ◽  
X Ray

The effect of the addition of Sn on the superconducting properties of the Bi 1.7 Pb 0.3 Sr 2 Ca 2 Cu 3 O y system as functions of Sn concentration and heat treatment has been studied by dc electrical resistance, ac magnetic susceptibility, and X-ray diffraction. Tin addition suppresses the volume fraction of the high T c phase. Samples with Sn > 0.1 show metallic behavior up to LNT. The formation of the Ca 2 PbO 4 phase is promoted by Sn. This depletes the amount of Pb and Ca necessary for the formation of the 2223 phase, thus reducing the volume fraction of the 2223 phase. It is possible that at least a small fraction of tin substitutes some of the cationic sites of the starting composition. The results of the different measurements are presented.

High Density Bulk Shape Rapid Consolidation of the Yba2Cu307-X Superconductor

1989 ◽  
Vol 169 ◽  
Author(s):  
S. V. Rele ◽  
R. V. Raman ◽  
H. S. Meeks ◽  
R. L. Anderson ◽  
R. N. Shelton ◽  
...  
Keyword(s):  
Volume Fraction ◽  
X Ray Diffraction ◽  
X Ray ◽  
Superconducting Volume Fraction ◽  
One Step ◽  
Hollow Cylinders ◽  
Diffraction Patterns ◽  
Set Up ◽  
Cylinders And Spheres ◽  
High Processing

AbstractA novel rapid densification technique for fabrication of bulk shape YBa2Cu307–xsuperconductor is presented. The Ceracon process is a one‐step, quasi‐isostatic consolidation route utilizing conventional P/M equipment and set‐up. The Ceracon technology has enabled successful fabrication of bulk, shapes such as discs, cylinders, hollow cylinders and spheres along with significant increases in the density up to 95‐98% of the theorertical. The superconducting volume fraction is preserved due to short hold times at the operating temperatures and avoidance of high processing temperatures. Results based on densities, microstructure, susceptibility measurements, X‐ray diffraction patterns and TGA measurements are discussed.

Magnetic Hardening of Mechanichally Alloyed SmFe11−xCoxTi

1999 ◽  
Vol 581 ◽  
Author(s):  
L. Bessais ◽  
C. Djega-Mariadassou
Keyword(s):  
Heat Treatment ◽  
Rietveld Method ◽  
Hexagonal Phase ◽  
X Ray Diffraction ◽  
Major Phase ◽  
X Ray ◽  
Different Temperatures ◽  
Magnetic Hardening ◽  
Property Changes ◽  
Nanocrystalline Phases

ABSTRACTMechanical alloying of ternary SmFe11−xCoxTi (x = 0, 0.5, 1, 1.5, 2) alloys was carried out under an Ar atmosphere. Milled samples were annealed for 30 min in a vacuum at different temperatures Ta from 650 °C to 1150 °C. The effects of heat treatment, on structure and magnetic property changes, have been investigated by means of x-ray diffraction using the Rietveld method, Mössbauer spectroscopy and differential sample magnetometer. Tetragonal ThMn12-type structure is observed for samples annealed at Ta > 900 °C. For 650<Ta<800 °C the TbCu7 type phase was identified as the major phase. Between these two regions a mixture of TbCu7 and ThMn12-type nanocrystalline phases is obtained with a maximum of the coercive field Hc (Hc > 5kOe). The Mössbauer spectra relative to the hexagonal phase show sextuplets broadened by the statistical occupancies of the iron sites. An enhancement of the magnetic properties results from the Co substitution.

Non-destructive measurement of the depth profile of the constituent in iron oxide scale by X-ray diffraction at SPring-8

2011 ◽  
Vol 1 (SRMS-7) ◽  
Author(s):  
M. Sato ◽  
T. Doi ◽  
Y. Hidaka ◽  
Y. Higashida ◽  
Y. Masaki ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Iron Oxide ◽  
Volume Fraction ◽  
Diffraction Measurement ◽  
Isothermal Heat Treatment ◽  
Oxide Scales ◽  
X Ray Diffraction ◽  
X Ray ◽  
Destructive Measurement ◽  
Non Destructive

The depth profiles of the constituent in iron oxide scales were investigated by X-ray diffraction measurement with controlling X-ray penetration depth at SPring-8. We successfully observed the interface region of scales non-destructively using X-ray with energy of 28 keV. The results indicated that the volume fraction ratio of Fe3O4 to FeO around the surface of samples increased by isothermal heat treatment. This suggested that the transformation of FeO to Fe3O4 due to isothermal heat treatment proceeds from surface into the inside of scale.

Synthesis and Superconducting Properties of Metastable Y(Ba2−xYx)Cu3O7+δ

1987 ◽  
Vol 99 ◽  
Author(s):  
Z. Iqbal ◽  
F. Reidinger ◽  
A. Bose ◽  
N. Cipollini ◽  
H. Eckhardt ◽  
...  
Keyword(s):  
Volume Fraction ◽  
Parent Compound ◽  
Resistive Transition ◽  
Superconducting Properties ◽  
X Ray Diffraction ◽  
X Ray ◽  
Recent Interest ◽  
Superconducting Volume Fraction ◽  
Citrate Precursor ◽  
Reaction Routes

ABSTRACTThe oxygen-deficient orthorhombic oxide YBa2Cu3O7-δ has been the center of intense recent interest because of its high Tc superconducting proper-ties[l-3]. Recently, the structurally related La3Ba3Cu3O15-δ, has received increasing attention[4–9]. The pure Y analog[10,11] cannot be synthesized by usual solid state reaction routes probably because of its metastability near 880°C. Here we report on the successful synthesis of pure tetragonal Y3,Ba3CU6O15-δ (referred to as Y 3–3–6), via the firing of an atomically mixed citrate precursor at a relatively low temperature. X-ray diffraction data characterize Y 3–3–6 to be isostructural with the corresponding La compound[4]. The unit cell composition can then be written as: Y(Ba2−x Yx) CU3O7+δ with the parent compound at x = 0.50. Specimens of Y 3–3–6 at × = 0.50 and 0.375 annealed at 650°C under 1 atmosphere of O2 are non-superconducting. Higher pressure O2 annealing and fluorine-doping leads to a 1–5% superconducting volume fraction with onset at 85K. Annealing near 880°C creates a 10% superconducting fraction which shows near-zero resistivity at 62K and a reproducible, small resistive transition near 260K.

Hydroxyapatite Coating on Ti-6Al-4V Alloy by an Electrolytic Process and with Heat-Treatment

2009 ◽  
Vol 631-632 ◽  
pp. 407-412
Author(s):  
Cheng Li Wang ◽  
Wei Jen Shih ◽  
Szu Hao Wang ◽  
Kuo Ming Chang ◽  
Wang Long Li ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Heat Treatment ◽  
Scanning Electron Microscopy ◽  
Calcium Phosphate ◽  
X Ray Diffraction ◽  
Xrd Pattern ◽  
Major Phase ◽  
X Ray ◽  
Electrolytic Process ◽  
Scanning Electron

The effect of the heat-treatment on the calcium phosphate deposited on Ti-6Al-4V substrate by an electrolytic process has been investigated. The calcium phosphate were deposited in a 0.04M Ca(H2PO4)2･H2O (MCPM) solution on Ti-6Al-4V substrate at 60 °C, 10V and 80 Torr for 1h, and calcined at different temperature for 4h. X-ray diffraction (XRD) and scanning electron microscopy (SEM) were used to characterized the deposited samples. The XRD pattern of as-deposited sample contain the phase of dicalcium phosphate (DCPD) and HAP. When calcined at 400 °C for 4 h, the DCPD phase is vanished and HAP becomes the major phase. The XRD pattern reveals that the intensity of HAP and Ca2P2O7 (CPP) decreases, but the β-TCP, CaO and rutile TiO2 also shows up.

Ex Situ Development of Y-Ti-O Nano Clusters

2015 ◽  
Vol 787 ◽  
pp. 622-626
Author(s):  
B. Anandan ◽  
S. Gopalakannan
Keyword(s):  
Heat Treatment ◽  
Volume Fraction ◽  
Large Population ◽  
Ex Situ ◽  
X Ray Diffraction ◽  
Scattered Electron ◽  
X Ray ◽  
Electron Mode ◽  
Nanoscale Clusters ◽  
Soaking Temperature

A high density nanoscale clusters of Y–Ti–O exhibit superior creep strength and potential for high resistance to radiation damage. X-Ray Diffraction is used to determine the formation of the complex nanoclusters (NCs). The formation of Y2TiO5NCs takes place during heat treatment of mechanically milled (MM) titanium and Yttria, and also it forms the mixture of Y2Ti2O5and Y2Ti2O7NCs during the high temperature soaking of MM iron, MM titanium and yttria. The microstructure of the hot consolidated mixture of MM iron, MM titanium and yttria were obtained through scanning electron microscopy (SEM). The back scattered electron mode is used to show the contrast between different elements in the microstructure. The increase in soaking temperature increases the size of the nanocluster, which decrease the volume fraction and number densities. A large population of nanoclusters precipitates during the heat treatment at high soaking temperature.

scholarly journals X-ray Determination of Compressive Residual Stresses in Spring Steel Generated by High-Speed Water Quenching

Materials ◽  
2019 ◽  
Vol 12 (7) ◽  
pp. 1154
Author(s):  
Diego E. Lozano ◽  
George E. Totten ◽  
Yaneth Bedolla-Gil ◽  
Martha Guerrero-Mata ◽  
Marcel Carpio ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Residual Stresses ◽  
High Speed ◽  
Spring Steel ◽  
X Ray Diffraction ◽  
Laboratory Equipment ◽  
X Ray ◽  
Water Chamber ◽  
Hardened Case ◽  
Compressive Residual Stresses

Automotive components manufacturers use the 5160 steel in leaf and coil springs. The industrial heat treatment process consists in austenitizing followed by the oil quenching and tempering process. Typically, compressive residual stresses are induced by shot peening on the surface of automotive springs to bestow compressive residual stresses that improve the fatigue resistance and increase the service life of the parts after heat treatment. In this work, a high-speed quenching was used to achieve compressive residual stresses on the surface of AISI/SAE 5160 steel samples by producing high thermal gradients and interrupting the cooling in order to generate a case-core microstructure. A special laboratory equipment was designed and built, which uses water as the quenching media in a high-speed water chamber. The severity of the cooling was characterized with embedded thermocouples to obtain the cooling curves at different depths from the surface. Samples were cooled for various times to produce different hardened case depths. The microstructure of specimens was observed with a scanning electron microscope (SEM). X-ray diffraction (XRD) was used to estimate the magnitude of residual stresses on the surface of the specimens. Compressive residual stresses at the surface and sub-surface of about −700 MPa were obtained.

scholarly journals Quartz Crystallite Size and Moganite Content as Indicators of the Mineralogical Maturity of the Carboniferous Chert: The Case of Cherts from Eastern Asturias (Spain)

Minerals ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 611
Author(s):  
Celia Marcos ◽  
María de Uribe-Zorita ◽  
Pedro Álvarez-Lloret ◽  
Alaa Adawy ◽  
Patricia Fernández ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Crystallite Size ◽  
Archaeological Sites ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Infrared And Raman Spectroscopy ◽  
First Time ◽  
Geological Formations

Chert samples from different coastal and inland outcrops in the Eastern Asturias (Spain) were mineralogically investigated for the first time for archaeological purposes. X-ray diffraction, X-ray fluorescence, transmission electron microscopy, infrared and Raman spectroscopy and total organic carbon techniques were used. The low content of moganite, since its detection by X-ray diffraction is practically imperceptible, and the crystallite size (over 1000 Å) of the quartz in these cherts would be indicative of its maturity and could potentially be used for dating chert-tools recovered from archaeological sites. Also, this information can constitute essential data to differentiate the cherts and compare them with those used in archaeological tools. However, neither composition nor crystallite size would allow distinguishing between coastal and inland chert outcrops belonging to the same geological formations.

scholarly journals First Report on the Geologic Occurrence of Natural Na–A Zeolite and Associated Minerals in Cretaceous Mudstones of the Paja Formation of Vélez (Santander), Colombia

Crystals ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 218
Author(s):  
Carlos Alberto Ríos-Reyes ◽  
German Alfonso Reyes-Mendoza ◽  
José Antonio Henao-Martínez ◽  
Craig Williams ◽  
Alan Dyer
Keyword(s):  
Natural Zeolite ◽  
Scanning Electron Micrographs ◽  
Total Sulfur ◽  
Zeolite A ◽  
X Ray Diffraction ◽  
X Ray ◽  
Mineral Phases ◽  
The World ◽  
Porosity And Permeability ◽  
First Time

This study reports for the first time the geologic occurrence of natural zeolite A and associated minerals in mudstones from the Cretaceous Paja Formation in the urban area of the municipality of Vélez (Santander), Colombia. These rocks are mainly composed of quartz, muscovite, pyrophyllite, kaolinite and chlorite group minerals, framboidal and cubic pyrite, as well as marcasite, with minor feldspar, sulphates, and phosphates. Total organic carbon (TOC), total sulfur (TS), and millimeter fragments of algae are high, whereas few centimeters and not biodiverse small ammonite fossils, and other allochemical components are subordinated. Na–A zeolite and associated mineral phases as sodalite occur just beside the interparticle micropores (honeycomb from framboidal, cube molds, and amorphous cavities). It is facilitated by petrophysical properties alterations, due to processes of high diagenesis, temperatures up to 80–100 °C, with weathering contributions, which increase the porosity and permeability, as well as the transmissivity (fluid flow), allowing the geochemistry remobilization and/or recrystallization of pre-existing silica, muscovite, kaolinite minerals group, salts, carbonates, oxides and peroxides. X-ray diffraction analyses reveal the mineral composition of the mudstones and scanning electron micrographs show the typical cubic morphology of Na–A zeolite of approximately 0.45 mμ in particle size. Our data show that the sequence of the transformation of phases is: Poorly crystalline aluminosilicate → sodalite → Na–A zeolite. A literature review shows that this is an unusual example of the occurrence of natural zeolites in sedimentary marine rocks recognized around the world.

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