Phase Equilibria in the System Tl-Ca-Ba-Cu-O. I. Stability of the 2122 Phase Under Conditions of Oxygen Annealing

1989 ◽  
Vol 169 ◽  
Author(s):  
L. P. Cook ◽  
C. K. Chiang ◽  
W. Wong-Ng ◽  
L. J. Swartzendruber ◽  
L. H. Bennett
Keyword(s):  
Heat Treatment ◽  
Magnetic Susceptibility ◽  
Phase Equilibria ◽  
Single Phase ◽  
Oxide Phase ◽  
X Ray Diffraction ◽  
Oxygen Annealing ◽  
X Ray ◽  
Long Duration ◽  
Annealing Experiments

AbstractResults are presented for 850°C oxygen annealing experiments (up to 62 hr) on the 2122 (Tl:Ca:Ba:Cu) oxide phase, with and without intermediate grinding. Samples were characterized by powder X-ray diffraction and a.c. magnetic susceptibility. The 2122 phase appears to be thermodynamically stable in oxygen under conditions of both extensive grinding, and, annealing of long duration. However, onset Tc's vary from 71 K to 109 K for apparently single-phase 2122 samples with nearly identical X-ray powder patterns, depending upon the heat treatment.

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.

Degradation of phenol by using magnetic photocatalysts of titania

2013 ◽  
Vol 67 (7) ◽  
pp. 1434-1441 ◽  
Author(s):  
Chiung-Fen Chang ◽  
I.-Peng Tseng
Keyword(s):  
Heat Treatment ◽  
Photocatalytic Activity ◽  
Single Phase ◽  
Health Impacts ◽  
X Ray Diffraction ◽  
Final Temperature ◽  
Soaking Time ◽  
X Ray ◽  
Green Materials ◽  
Diffraction Patterns

Magnetic TiO2 (MT) composites were prepared and applied to degrading phenol, which is one of the listed priority pollutants. The effects of heat treatment under preparation on the photocatalytic activity of MT composites have been investigated by varying the soaking time under a constant final temperature of 823 K. The total organic carbon and ring-remaining intermediates of o-DHB, p-DHB and 1,4-BQ in solution were detected during the photodegradation of phenol. All the resulting MT composites were the single-phase anatase and magnetite judged by X-ray diffraction patterns. The calcination of the as-prepared particles was proven to be extremely crucial to the photocatalytic activity. The best condition of heat treatment was found to be soaking time of 2 h at T = 823 K due to the good performance of photocatalytic activity, stable magnetic property, and reusability over three times. The results lead to the conclusion that recyclable MT composites prepared in this study, which belonged to the category of recyclable green materials, exhibit good photocatalytic activity to degrade phenol so as to possess applicable potential for the degradation of refractory organics in the aqueous solution. Furthermore, the environmental and health impacts were reduced as MT composites were applied in the treatment of water pollution.

The location and effects of Si in (Ti1–xSix)Ny thin films

2009 ◽  
Vol 24 (8) ◽  
pp. 2483-2498 ◽  
Author(s):  
Axel Flink ◽  
Manfred Beckers ◽  
Jacob Sjölén ◽  
Tommy Larsson ◽  
Slawomir Braun ◽  
...  
Keyword(s):  
Thin Films ◽  
Grain Boundaries ◽  
Photoelectron Spectroscopy ◽  
Single Phase ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Arc Evaporation ◽  
Annealing Experiments ◽  
Tissue Phase

(Ti1–xSix)Ny (0 ≤ x ≤ 0.20; 0.99 ≤ y(x) ≤ 1.13) thin films deposited by arc evaporation have been investigated by analytical transmission electron microscopy, x-ray diffraction, x-ray photoelectron spectroscopy, and nanoindentation. Films with x ≤ 0.09 are single-phase cubic (Ti,Si)N solid solutions with a dense columnar microstructure. Films with x > 0.09 have a featherlike microstructure consisting of cubic TiN:Si nanocrystallite bundles separated by metastable SiNz with coherent-to-semicoherent interfaces and a dislocation density of as much as 1014 cm−2 is present. The films exhibit retained composition and hardness between 31 and 42 GPa in annealing experiments to 1000 °C due to segregation of SiNz to the grain boundaries. During annealing at 1100–1200 °C, this tissue phase thickens and transforms to amorphous SiNz. At the same time, Si and N diffuse out of the films via the grain boundaries and TiN recrystallize.

Karakterisasi Struktur Kristal dan Sifat Magnetik Magnet Stronsium Ferit Pasir Besi Batang Sukam Kabupaten Sijunjung Sumatera Barat

2017 ◽  
Vol 1 ◽  
pp. 38
Author(s):  
Arif Budiman ◽  
Dwi Puryanti ◽  
Sri Mulyadi Dt. Basa ◽  
Muhammad Rizki ◽  
Helfi Syukriani
Keyword(s):  
Crystal Structure ◽  
Magnetic Properties ◽  
Magnetic Susceptibility ◽  
Single Phase ◽  
Oxidation Process ◽  
Strontium Ferrite ◽  
X Ray Diffraction ◽  
Hexagonal Crystal ◽  
X Ray

<p><strong>Abstract:</strong> The synthesis and characterization of the crystal structure and magnetic properties of strontium ferrite magnets (SrO.6Fe<sub>2</sub>O<sub>3</sub>) has been done. Hematite (Fe<sub>2</sub>O<sub>3</sub>) is synthesized from iron sand of Batang Sukam Sijunjung Sumatera Barat through the oxidation process by temperature 700ºC for 3.0 hours. Strontium carbonate (SrCO<sub>3</sub>) was obtained from Merck product with a purity of more than 99%. Synthesis of strontium ferrite magnets are made through a process of solid-solid mixing and sintering at a temperature of 1000ºC for 3.0 hours. The results of characterization of X-ray diffraction indicates that it has formed a single phase strontium ferrite magnets with a hexagonal crystal structure. The result of measurement of the magnetic properties shows that an average magnetic susceptibility of strontium ferrite magnet is 266.7 × 10<sup>-8 </sup>m<sup>3</sup> /kg.</p><p> </p><p><strong>Keywords</strong>: strontium ferrite magnet, iron sand, crystal structure and magnetic susceptibility.</p><p><strong> </strong></p><p><strong>Abstrak:</strong> Telah dilakukan sintesis dan karakterisasi struktur kristal dan sifat magnetik magnet stronsium ferit (SrO.6Fe<sub>2</sub>O<sub>3</sub>). Hematit (Fe<sub>2</sub>O<sub>3</sub>) disintesis daripasir besi Batang Sukam Kabupaten Sijunjung Sumatera Barat melalui proses oksidasi dengan temperatur 700ºC selama 3,0 jam. Stronsium karbonat (SrCO<sub>3</sub>) diperoleh dari produk Merck dengan kemurnian lebih dari 99 %. Sintesis magnet stronsium ferit dibuat melalui proses <em>solid-solid mixing</em> dan disintering pada suhu 1000ºC selama 3,0 jam. Hasil karakterisasi difraksi sinar-X menunjukkan bahwa telah terbentuk <em>single phase</em> magnet stronsium ferit dengan struktur kristal heksagonal. Hasil pengukuran sifat magnet menunjukkan bahwa magnet stronsium ferit memiliki suseptibilitas magnetik rata-rata 266,7 × 10<sup>-8</sup> m<sup>3</sup>/kg.</p><p> </p><p><strong>Kata Kunci:</strong> magnet stronsium ferit, pasir besi, struktur kristal dan suseptibilitas magnetik.</p>

Magnetic and 119-Sn Mössbauer Effect Study of Sn-Doped Pb2Sr2Eu.5Cu3-xSnxO8+z (x = 0.0, 0.1) Superconductors

1989 ◽  
Vol 169 ◽  
Author(s):  
P. P. Vaishnava ◽  
C. D. Nelson ◽  
W. P. Pratt
Keyword(s):  
Magnetic Susceptibility ◽  
Mössbauer Effect ◽  
Single Phase ◽  
Effect Study ◽  
Site Symmetry ◽  
X Ray Diffraction ◽  
Mossbauer Effect ◽  
X Ray ◽  
Fraction Increase ◽  
Meissner Fraction

AbstractX-ray diffraction, magnetic susceptibility and 119-Sn Mössbauer effect measurements have been performed on Pb2Sr2Eu.5Cu3-xSnx08+z (x = 0.0, 0.1) superconductors. The x-ray diffraction pattern indicated that the samples are single phase materials. The diamagnetic shielding and the Meissner fraction increase with the introduction of Sn in the lattice. The 119-Sn Mössbauer effect measurements have been used to determine the site symmetry and valence state of Sn atom in the superconductor.

CHEMCIAL TAILORING OF ELECTRONIC DOPING IN YSr2Cu3O7±d SUPERCONDUCTOR

2003 ◽  
Vol 17 (04n06) ◽  
pp. 685-689 ◽  
Author(s):  
E. GILIOLI ◽  
F. LICCI ◽  
A. PRODI ◽  
A. GAUZZI ◽  
M. MAREZIO
Keyword(s):  
Magnetic Susceptibility ◽  
Carrier Concentration ◽  
Single Phase ◽  
Temperature Measurements ◽  
Secondary Phases ◽  
X Ray Diffraction ◽  
Al Doping ◽  
Dynamic Vacuum ◽  
X Ray ◽  
Electronic Doping

With the aim to optimize the carrier concentration and T c of YSr 2 Cu 3 O 7± d (YSCO), we studied the effects of aliovalent substituents for Y and Cu1 in both as-prepared and annealed samples. Ca 2+ and Ce 4+ and Al 3+ were substituted for Y and Cu1, respectively. The samples were synthesized at 1050°C, under a pressure of 30 Kbar, in a multi-anvil apparatus. The post-preparation annealings were carried out in static oxygen, nitrogen or under dynamic vacuum. The samples were characterized by X-ray diffraction and found to be almost single-phase at doping concentrations ≤ 10%. T c was determined by resistivity and magnetic susceptibility Vs temperature measurements. It was found to decrease in Ca-doped samples, to slightly increase for Al-doping or to remain almost constant for Ce-doping. These results seem to support the hypothesis that as-prepared YSCO is overdoped. For any substitution > 10%, T c decreased or vanished and the samples had a high content of secondary phases. T c of doped compounds also decreases after post-preparation annealings.

ON THE ULTRASONIC ANOMALIES NEAR 260 K IN Y1Ba2Cu4O8

1999 ◽  
Vol 13 (21) ◽  
pp. 743-749 ◽  
Author(s):  
A. T. WU
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Susceptibility ◽  
Single Phase ◽  
Ultrasonic Waves ◽  
X Ray Diffraction ◽  
X Ray ◽  
Long Wavelength ◽  
Quadrupole Resonance ◽  
Spin Excitations ◽  
Nuclear Quadrupole

Single phase polycrystalline high-T c superconductor Y 1 Ba 2 Cu 4 O 8 (Y124) has been measured by employing longitudinal and transverse ultrasonic waves, low-temperature X-ray diffraction, and specific heat. Comparison of the obtained data with the data of nuclear quadrupole resonance, nuclear magnetic resonance, and magnetic susceptibility measurements available in the literature from other groups implies the opening of a pseudospin gap near 260 K in Y124. It is proposed that the ultrasonic anomalies observed in Y124 near 260 K originate from the interactions between ultrasonic waves and long wavelength spin excitations.

Raman And Fluorescence Spectra Observed in Laser Microprobe Measurements of Several Compositions in the Ln-Ba-Cu-O System

1990 ◽  
Vol 48 (2) ◽  
pp. 278-279
Author(s):  
Edgar S. Etz ◽  
Thomas D. Schroeder ◽  
Winnie Wong-Ng
Keyword(s):  
Fluorescence Spectra ◽  
Single Phase ◽  
X Ray Diffraction ◽  
Ceramic Powders ◽  
Conventional Solid State Reaction ◽  
X Ray ◽  
Raman Microprobe ◽  
Methods Of Synthesis ◽  
Compositional Homogeneity ◽  
Processing Techniques

We are investigating by Raman microprobe measurements the superconducting and related phases in the LnBa2Cu3O7-x (for x=0 to 1) system where yttrium has been replaced by several of the lanthanide (Ln = Nd,Sm,Eu,Ho,Er) elements. The aim is to relate the observed optical spectra (Raman and fluorescence) to the compositional and structural properties of these solids as part of comprehensive materials characterization. The results are correlated with the methods of synthesis, the processing techniques of these materials, and their superconducting properties. Of relevance is the substitutional chemistry of these isostructural systems, the differences in the spectra, and their microanalytical usefulness for the detection of impurity phases, and the assessment of compositional homogeneity. The Raman spectra of most of these compounds are well understood from accounts in the literature.The materials examined here are mostly ceramic powders prepared by conventional solid state reaction techniques. The bulk samples are of nominally single-phase composition as determined by x-ray diffraction.

Observation of pseudo 10-fold symmetry in the ordered iron-zinc delta phase

1992 ◽  
Vol 50 (1) ◽  
pp. 36-37
Author(s):  
L. A. Giannuzzi ◽  
A. S. Ramani ◽  
P. R. Howell ◽  
H. W. Pickering ◽  
W. R. Bitler
Keyword(s):  
Single Phase ◽  
X Ray Diffraction ◽  
Rich Region ◽  
Average Cell ◽  
X Ray ◽  
Delta Phase ◽  
Cell Dimensions ◽  
Δ Phase ◽  
Morphological Differences ◽  
Concentration Discontinuity

The δ phase is a Zn-rich intermetallic, having a composition range of ∼ 86.5 - 92.0 atomic percent Zn, and is stable up to 665°C. The stoichiometry of the δ phase has been reported as FeZn7 and FeZn10 The deviation in stoichiometry can be attributed to variations in alloy composition used by each investigator. The structure of the δ phase, as determined by powder x-ray diffraction, is hexagonal (P63mc or P63/mmc) with cell dimensions a = 1.28 nm, c = 5.76 nm, and 555±8 atoms per unit cell. Later work suggested that the layer produced by hot-dip galvanizing should be considered as two distinct phases which are characterized by their morphological differences, namely: the iron-rich region with a compact appearance (δk) and the zinc-rich region with a columnar or palisade microstructure (δp). The sub-division of the δ phase was also based on differences in diffusion behavior, and a concentration discontinuity across the δp/δk boundary. However, work utilizing Weisenberg photographs on δ single crystals reported that the variation in lattice parameters with composition was small and hence, structurally, the δk phase and the δp phase were the same and should be thought of as a single phase, δ. Bastin et al. determined the average cell dimensions to be a = 1.28 nm and c = 5.71 nm, and suggested that perhaps some kind of ordering process, which would not be observed by x-ray diffraction, may be responsible for the morphological differences within the δ phase.

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.

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