Formation of Metastable Structures and Amorphous Phases in cu-w Alloys Using the Triode Sputtering Technique

1988 ◽  
Vol 100 ◽  
Author(s):  
H. F. Rizzo ◽  
L. E. Tanner ◽  
M. A. Wall ◽  
T. B. Massalski ◽  
E. D. McClanahan
Keyword(s):  
Amorphous Alloys ◽  
Lattice Parameter ◽  
Near Neighbor ◽  
X Ray Diffraction ◽  
Amorphous Phases ◽  
Metastable Structures ◽  
Vegard’S Law ◽  
Wide Range ◽  
Bcc Phase ◽  
Near Neighbor Distance

ABSTRACTThe triode sputtering technique and a “split-target” arrangement were used to produce metastable crystalline and amorphous phases in the Cu-W system under essentially oxygen-free conditions. Large metastable extensions of solid solubility were observed both from the Cu (fcc) and W (bcc) sides of the phase diagram, and a wide range of metallic glass formation was observed, approximately between 30 and 65 at.% W. The thickness of the amorphous Cu-W phase (40–160 pm) that can be deposited without the formation of the metastable bcc phase appears to be dependent on the Cu-W alloy composition. On heating, the crystallization temperature of the amorphous alloys was higher than 350°C. The behavior of the lattice parameter and near-neighbor distance has been studied with x-ray diffraction, showing small positive deviations from an assumed Vegard's Law. Hardness measurements indicate that the metastable crystalline phases are relatively harder than the amorphous phase.

Investigation of Amorphous/Crystalline State in Cu-Hf-Al Alloys

2010 ◽  
Vol 649 ◽  
pp. 87-92
Author(s):  
E. Nagy ◽  
Viktória Rontó ◽  
Jenő Sólyom ◽  
András Roósz
Keyword(s):  
Amorphous Alloys ◽  
Great Influence ◽  
Amorphous State ◽  
High Strength ◽  
Al Alloys ◽  
X Ray Diffraction ◽  
X Ray ◽  
Wide Range ◽  
Different Shapes ◽  
Important Purpose

Cu-Hf-Al alloys are considered to be relatively new ones among Cu-based bulk amorphous alloys. Cu-Hf-Al alloys have high strength in amorphous state and this property makes many applications feasible for the industry. During the production of amorphous alloys the most important purpose is to produce them in the biggest diameter to make them suitable for a wide range of applications. The circumstances of the production process have a great influence on the developing structure. In the present work solidification of Cu-Hf-Al alloys were investigated. The alloys were cast into different shapes with different Al contents with special regard to the appearance of the amorphous/crystalline structure. The appearance and the structure of crystalline phases were determined by X-ray diffraction and X-ray, DSC and metallographic measurements were used to investigate the developing structure.

scholarly journals Effects Of Cd On Physical And Some Magnetic Properties Of Co-Cd Ferrites

1970 ◽  
Vol 35 (2) ◽  
pp. 229-235 ◽  
Author(s):  
Saroaut Noor ◽  
SS Sikder ◽  
M Samir Ullah ◽  
MA Hakim ◽  
Shireen Akhter
Keyword(s):  
Curie Temperature ◽  
Lattice Parameter ◽  
Initial Permeability ◽  
X Ray Diffraction ◽  
Ceramic Method ◽  
X Ray ◽  
Cobalt Ferrites ◽  
Vegard’S Law ◽  
Ray Density ◽  
Curie Temperature Tc

Polycrystalline samples of Cd substituted cobalt ferrites with composition Co1-xCdxFe2O4 (x = 0.0- 0.6 in steps of 0.1) were prepared by double sintering ceramic method. The samples were sintered at 1050°C for 3 hours. X-ray diffraction pattern of the samples showed single phase cubic spinel structure. It was found that the lattice parameter increases linearly with increasing Cd content following Vegard’s law. The apparent density and X-ray density exhibited similar behavior. The Curie temperature Tc has been determined from the temperature dependence of permeability. It was found that the Curie temperature continuously decreased with increasing Cd content and is attributed to the weakening of JAB exchange interaction. The initial permeability, μ' increases with increasing Cd content up to x = 0.6 and then decreases. Key words: Co-Cd ferrite; Lattice parameter; Permeability DOI: http://dx.doi.org/10.3329/jbas.v35i2.9429 JBAS 2011; 35(2): 229-235

Characterization of the Aurivillius Type PbBi4Ti4O15 Piezoelectric Ceramic Doped with Eu3+

2006 ◽  
Vol 45 ◽  
pp. 2483-2488
Author(s):  
L. Pablos ◽  
Maria Elena Villafuerte-Castrejón ◽  
A. Ibarra-Palos ◽  
J. Ocotlán-Flores ◽  
R. Sato ◽  
...  
Keyword(s):  
Piezoelectric Ceramic ◽  
Solubility Limit ◽  
Lattice Parameter ◽  
Layered Oxides ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Density Measurements ◽  
X Ray ◽  
Wide Range

PbBi4Ti4O15 belongs to the bismuth oxide layers family discovered by Aurivillius more than 50 years ago. In the last few years, there has been considerable interest in layered oxides exhibiting ferroelectric, piezoelectric and other related properties due to their wide range of application in technical devices. In the present work the PbBi4Ti4O15 solid solution formed with Eu3+ was synthesized by coprecipitation method and solubility limit was found. All compounds were characterized by scanning electron microscopy, density measurements and X-ray diffraction. The variation of lattice parameter with the Eu3+ concentration was obtained. Raman spectroscopy was carried out in order to determine the Eu3+ site in the lattice. Thermal analysis (thermogravimetry and differencial scanning calorimetry) results are also presented.

Auto ignition synthesis of nanocrystalline MgAl2O4 and related nanocomposites

1999 ◽  
Vol 14 (9) ◽  
pp. 3571-3580 ◽  
Author(s):  
S. Bhaduri ◽  
S. B. Bhaduri ◽  
K. A. Prisbrey
Keyword(s):  
Solid Solutions ◽  
Lattice Parameter ◽  
Nanocrystalline Powders ◽  
Ignition Process ◽  
X Ray Diffraction ◽  
Grain Sizes ◽  
Auto Ignition ◽  
Transmission Electron ◽  
Vegard’S Law ◽  
20 Nm

Nanocrystalline powders of various compositions in the Al2O3–MgO binary system were synthesized using a novel “auto ignition” process. The respective nitrates were used as starting materials and urea as fuel. Thermodynamic calculations of the adiabatic temperatures were performed for various compositions from Al2O3-rich to the MgO-rich side of the phase diagram. The combustion temperatures of the different compositions were also determined experimentally. The as-synthesized powders were characterized by x-ray diffraction (XRD) and transmission electron microscopy (TEM). As a result of processing, spinel, alumina, magnesia, and solid solutions/ nanocomposites thereof formed. Grain sizes and the lattice parameter were calculated based on XRD results. Where appropriate, the lattice parameter versus the composition of these solid solutions satisfied Vegard's law. Spinel grains were in the 13–20 nm range, alumina grains were 30–40 nm, and MgO grains were 2–28 nm. The grain sizes calculated from XRD results were in good agreement with the TEM results.

Combined High-Resolution and Analytical TEM Studies of Phase-Separated Alloys

1980 ◽  
Vol 38 ◽  
pp. 176-177
Author(s):  
C. K. Wu ◽  
A. F. Marshall ◽  
G. Thomas ◽  
R. Sinclair
Keyword(s):  
High Resolution ◽  
Alloy System ◽  
Lattice Parameter ◽  
X Ray Diffraction ◽  
Lattice Imaging ◽  
Experimental Conditions ◽  
X Ray ◽  
Analytical Technique ◽  
Vegard’S Law ◽  
Direct Technique

The determination of composition variations due to alloy phase transformations has long been of interest to materials scientists. In this paper, data obtained in the same alloy system using conventional x-ray diffraction analysis, high resolution lattice imaging and the analytical technique of STEM/EDS are compared, and their application to various systems is discussed. Composition is experimentally correlated with lattice parameter measurements or, for species of similar sizes, determined by assuming Vegard's law. X-ray diffraction gives a more accurate lattice parameter measurement but the information is averaged over a large specimen volume and cannot be used for coherent precipitate systems. Lattice imaging, on the other hand, resolves lattice spacings in microareas (<20 Å) of the structure, but is limited in accuracy by magnification determination, imaging conditions and precision in measuring fringe spacings.1 STEM/EDS, with a resolution under optimum conditions of 100-200 Å, is a more direct technique for composition determination since the characteristic x-ray intensity produced by the specimen is directly proportional to the composition. However, a number of spurious events may occur to alter the x-ray intensities seen by the detector and accuracy depends greatly on the experimental conditions and the nature of the specimen.2

scholarly journals Bi-based high Tc superconducting fibers by melt extraction

1992 ◽  
Vol 7 (9) ◽  
pp. 2365-2372
Author(s):  
J.J. Chang ◽  
G. Rudkowska ◽  
A. Zaluska ◽  
P. Rudkowski ◽  
J.O. Ström-Olsen ◽  
...  
Keyword(s):  
Crystallization Process ◽  
Lattice Parameter ◽  
Squid Magnetometry ◽  
X Ray Diffraction ◽  
Initial Composition ◽  
Scanning Calorimetry ◽  
High Tc ◽  
X Ray ◽  
Melt Extraction ◽  
Bcc Phase

Bismuth-based high Tc superconductors have been prepared as fibers by a technique of melt extraction. As-made, the fibers are amorphous with diameters ranging from 0.7 μm to 100 μm and lengths of up to 5 cm. The fibers were subsequently transformed into high Tc superconductors by heat treatment in air. Superconducting transitions at 105 K and 82 K were measured in annealed fibers of initial composition Bi1.8Pb0.2Sr2Ca3Cu4Ox by SQUID magnetometry. The volume fractions of superconducting phases were estimated to have lower bounds of 30% for 2212 and 5% for 2223. The crystallization process has been studied by differential scanning calorimetry, electron microscopy, and x-ray diffraction. Crystallization involves first the formation of the Bi-2201 phase and a bcc phase with lattice parameter a = 0.425 nm before finally significant fractions of both the Bi-2212 and Bi-2223 phases are formed.

scholarly journals Thermophysical and anion diffusion properties of (U x ,Th 1− x )O 2

2014 ◽  
Vol 470 (2171) ◽  
pp. 20140427 ◽  
Author(s):  
Michael W. D. Cooper ◽  
Samuel T. Murphy ◽  
Paul C. M. Fossati ◽  
Michael J. D. Rushton ◽  
Robin W. Grimes
Keyword(s):  
Thermal Expansion ◽  
Specific Heat ◽  
Solid Solutions ◽  
Defect Formation ◽  
Linear Thermal Expansion ◽  
Lattice Parameter ◽  
Thermal Dependence ◽  
Vegard’S Law ◽  
Wide Range ◽  
Superionic Transition

Using molecular dynamics, the thermophysical properties of the (U x ,Th 1− x )O 2 system have been investigated between 300 and 3600 K. The thermal dependence of lattice parameter, linear thermal expansion coefficient, enthalpy and specific heat at constant pressure is explained in terms of defect formation and diffusivity on the oxygen sublattice. Vegard's law is approximately observed for solid solution thermal expansion below 2000 K. Different deviations from Vegard's law above this temperature occur owing to the different temperatures at which the solid solutions undergo the superionic transition (2500–3300 K). Similarly, a spike in the specific heat, associated with the superionic transition, occurs at lower temperatures in solid solutions that have a high U content. Correspondingly, oxygen diffusivity is higher in pure UO 2 than in pure ThO 2 . Furthermore, at temperatures below the superionic transition, oxygen mobility is notably higher in solid solutions than in the end members. Enhanced diffusivity is promoted by lower oxygen-defect enthalpies in (U x ,Th 1− x )O 2 solid solutions. Unlike in UO 2 and ThO 2 , there is considerable variety of oxygen vacancy and oxygen interstitial sites in solid solutions generating a wide range of property values. Trends in the defect enthalpies are discussed in terms of composition and the lattice parameter of (U x ,Th 1− x )O 2 .

scholarly journals The effect of Bi additives on the properties of Fe-Pt films

2019 ◽  
Vol 27 (2) ◽  
pp. 47-50
Author(s):  
V. F. Bashev ◽  
N. A. Kutseva ◽  
O. I. Kushnerov ◽  
S. I. Ryabtsev ◽  
O. V. Yelina ◽  
...  
Keyword(s):  
Coercive Force ◽  
X Ray Diffraction ◽  
Ceramic Substrates ◽  
Amorphous Phases ◽  
Sputtered Films ◽  
Plasma Sputtering ◽  
Ion Plasma ◽  
Metastable Structures ◽  
Nanocrystalline And Amorphous ◽  
Pt Films

Using the modernized three-electrode ion-plasma sputtering method, homogeneous thin films of FePt and Fe (Pt/Bi) were obtained. Films were deposited on NaCl and glass-ceramic substrates. The film thickness was 120-530 nm. In this case, the calculated cooling rate reached ~ 1012–1014 K/s. The structure of the FePt and Fe (Pt/Bi) films was investigated using X-ray diffraction and electron microscopy methods. It was established that metastable phases were formed in freshly sputtered films, including a supersaturated solid solution, a nanocrystalline and amorphous phases. It was determined that the obtained metastable structures are stable when heated to 540-880 K, depending on the composition. It was established that Bi additives significantly reduce the coercive force of films in the as-sputtered state. It was shown that a heat treatment increased the coercive force up to 36 kA/m in FePt films and up to 10 kA/m in Fe (Pt/Bi) films. The composition of Fe (Pt/Bi) films with a small value of the temperature coefficient of resistance (TCR ~3·10-5 K-1) was determined.

Amorphous Phase Separation in Vapor-Quenched Cu-Zr

1981 ◽  
Vol 39 ◽  
pp. 274-275
Author(s):  
A. F. Marshall ◽  
R. G. Walmsley
Keyword(s):  
X Ray Diffraction ◽  
Ion Milling ◽  
Scanning Calorimetry ◽  
Two Phase ◽  
Amorphous Phases ◽  
Wide Range ◽  
Magnetron Sputter Deposition ◽  
Magnetron Sputter ◽  
Sputter Deposited ◽  
Beam Currents

Noncrystalline Cu-Zr alloys can be formed by liquid or vapor quench techniques over a wide range of compositions. These noncrystalline structures are typically homogeneous. We have recently observed a microstructure apparently composed of two amorphous phases in noncrystalline sputter-deposited Cu-Zr at a composition of 40 at% Zr. The occurrence of two amorphous phases in this material was also indicated by x-ray diffraction, differential scanning calorimetry, and electrochemical measurements. The purpose of this paper is to confirm and characterize the two-phase microstructure using the analytical electron microscope.The CuZr films were formed by magnetron sputter deposition in a phase spread mode, i.e., separated Cu and Zr sputtering sources producing a range of compositions on the static substrate. TEM specimens at the composition 40 at% Zr were prepared by ion milling. It was necessary to mill at very low beam currents to avoid excessive heating of the specimen and consequent changes in the microstructure.

Lattice Parameter Determination of Textured Co81−xCr15PtxTa4 Thin Films

1999 ◽  
Vol 562 ◽  
Author(s):  
B. Lu ◽  
S. D. Harkness ◽  
W. A. Lewis ◽  
D. E. Laughlin ◽  
D. N. Lambeth
Keyword(s):  
Thin Films ◽  
Electron Diffraction ◽  
Lattice Parameter ◽  
Parameter Determination ◽  
X Ray Diffraction ◽  
X Ray ◽  
Vegard’S Law ◽  
Variation Rate ◽  
Sputter Deposited

ABSTRACTThe thin films Co81−xCr15PtxTa4 with (0002) crystallographic texture have been sputter deposited with and without substrate bias. The lattice parameter of the thin films has been determined by a combination of x-ray diffraction and electron diffraction techniques. The resolution of the electron diffraction was enhanced by a digital imaging technique. The variation rate of the a lattice parameter with Pt content is consistent with Vegard's law. The change in the c lattice parameter is much greater than what is expected from Vegard's law.

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