Equilibrium phase diagram for the system PbO-CaO-CuO

1990 ◽  
Vol 5 (5) ◽  
pp. 929-931 ◽  
Author(s):  
Hitoshi Kitaguchi ◽  
Jun Takada ◽  
Kiichi Oda ◽  
Yoshinari Miura
Keyword(s):  
Eutectic Reaction ◽  
Equilibrium Phase ◽  
Eutectic Point ◽  
Equilibrium Phase Diagram ◽  
X Ray Diffraction ◽  
Subsolidus Phase ◽  
Essential Information ◽  
X Ray ◽  
Subsolidus Phase Equilibrium ◽  
System Phase

In order to obtain essential information on the formation process of the high-Tc phase in the Bi, Pb-Sr-Ca-Cu-O system, phase equilibria in the system PbO-CaO-CuO have been studied, mainly by x-ray diffraction analysis and thermal analysis. Temperature versus composition diagrams were established for the systems PbO-CuO(Cu2O) and PbO(PbO2)–CaO in air. Three invariant points were detected in these systems: a eutectic reaction (PbO + Ca2PbO4 = L) at 847 ± 6°C, a peritectic reaction (Ca2PbO4 = L + CaO) at 980 ± 2°C, and a eutectic reaction (PbO + CuO = L) at 789 ± 3°C. For the system PbO(PbO2)-CaO-CuO, subsolidus phase equilibrium in air was established. The liquidus was also examined at 780, 800, and 820°C, and a ternary (PbO-Ca2PbO4-CuO) eutectic point was detected at 772 ± 6°C.

Equilibrium phase diagrams in the system CuO–PbO–Ag

1995 ◽  
Vol 10 (11) ◽  
pp. 2933-2937 ◽  
Author(s):  
H.K. Liu ◽  
S.X. Dou ◽  
M. Ionescu ◽  
Z.B. Shao ◽  
K.R. Liu ◽  
...  
Keyword(s):  
High Temperature Superconductor ◽  
Eutectic Reaction ◽  
Critical Role ◽  
Equilibrium Phase ◽  
Eutectic Point ◽  
X Ray Diffraction ◽  
X Ray ◽  
Liquid Phases ◽  
Tie Lines ◽  
Xrd Techniques

Silver has played a critical role for the fabrication of metal/high temperature superconductor composites. Phase equilibrium and microstructure in the ternary PbO-CuO-Ag system have been investigated using differential thermal analysis (DTA), thermogravimetry (TG), scanning electron microscope (SEM), and x-ray diffraction (XRD) techniques. Composition versus temperature diagrams have been established for these systems in air. In the ternary CuO-PbO-Ag system, there is a eutectic reaction CuO + PbO + Ag = L at 750 °C and a composition of 12.04 mol % Ag, 16.35 mol % CuO, and 72.62 mol % PbO. Two immiscible regions near the two binary tie lines PbO-Ag and CuO-Ag were detected. No binary or ternary compound was detected in these systems. SEM and EDS results confirm the presence of two liquid phases and the eutectic point

X-ray diffraction and x-ray photoelectron spectroscopy study of the Ru–Cu/SiO2 system prepared by low temperature reduction: Occurrence of a metastable amorphous or nanocrystalline phase

1996 ◽  
Vol 11 (2) ◽  
pp. 325-331 ◽  
Author(s):  
Maurizio Lenarda ◽  
Renzo Ganzerla ◽  
Loretta Storaro ◽  
Romana Frattini ◽  
Stefano Enzo ◽  
...  
Keyword(s):  
Photoelectron Spectroscopy ◽  
Surface Composition ◽  
Equilibrium Phase ◽  
Equilibrium Phase Diagram ◽  
Ruthenium Catalysts ◽  
Nanocrystalline Phase ◽  
X Ray Diffraction ◽  
X Ray ◽  
Hexagonal Close Packed ◽  
Metallic Salts

Bimetallic copper-ruthenium catalysts supported on silica were prepared by the reduction of the metallic salts in aqueous solution at room temperature. The concentration of the two metal components was selected to span the entire range of composition. In spite of the known immiscibility for the copper-ruthenium equilibrium phase diagram, X-Ray Diffraction (XRD) measurements combined with X-ray Photoelectron Spectroscopy (XPS) data indicate that this method of preparation is able to produce nanocrystalline extended solid solutions and/or amorphous metastable phases. In the case of ruthenium-rich compositions, the hexagonal close-packed (hcp) ruthenium crystallites are covered by copper atoms which grow with the same hcp sequence of the ruthenium core. For intermediate compositions a nanocrystalline and/or amorphous phase is observed, while in the case of copper-rich samples a single-phase fcc extended solid solution is found. The surface composition of the samples appears systematically enriched with Cu, as obtained from XPS semiquantitative results. The phenomena of phase separation and growth induced by thermal annealing at 870 K are also presented and discussed.

Structural Properties of β-FeSi2 Bulk Crystal Grown by Horizontal Gradient Freeze Method

1995 ◽  
Vol 402 ◽  
Author(s):  
H. Kakemoto ◽  
Y. Tsaic ◽  
A. C. Beye ◽  
H. Katsumata ◽  
S. Sakuragi ◽  
...  
Keyword(s):  
High Purity ◽  
Equilibrium Phase ◽  
Equilibrium Phase Diagram ◽  
Growth Conditions ◽  
Horizontal Gradient ◽  
X Ray Diffraction ◽  
X Ray ◽  
Β Phase ◽  
Α Phase ◽  
Micro Analysis

AbstractWe report on the synthesis of β-FeSi2 bulk materials using Horizontal Gradient Freeze (HGF) method. Chunk and powder FeSi2 or high-purity Fe (4N) and Si (9N) were used as starting materials. Three values (1:2, 2:5 and 1:3) of the Fe:Si ratio were selected in the very narrow α and β ranges of the equilibrium phase diagram. Samples were melted between 1300°C and 1500°C in high purity graphite crucibles covered with boron nitride. After cooling, the samples were kept at 800°C and 900°C during 66 to 100 hours, leading to transformation from α to β phase. Cooling rate and annealing time were taken as the two main parameters to optimize the growth conditions. Principal structural characterization was made by X-ray diffraction (XRD). Correlation with stoichiometry was achieved using the results of Rutherford Backscattering Spectroscopy (RBS) and Electron Probe X-Ray Micro Analysis (EPXMA). The samples obtained from 1:2 ratio exhibited mainly β phase while the 2:5 ratio specimens revealed almost α phase structure. The samples prepared with 1:3 ratio was found as a mixture of α and β phases under Si-rich conditions.

Equilibrium phase diagrams for the systems PbO–SrO–CuO and PbO–CaO–SrO

1990 ◽  
Vol 5 (7) ◽  
pp. 1397-1402 ◽  
Author(s):  
Hitoshi Kitaguchi ◽  
Jun Takada ◽  
Kiichi Oda ◽  
Yoshinari Miura
Keyword(s):  
Solid Solution ◽  
Equilibrium Phase ◽  
Xrd Analysis ◽  
Hexagonal Structure ◽  
Lattice Parameters ◽  
Subsolidus Phase ◽  
Essential Information ◽  
Solubility Range ◽  
Subsolidus Phase Equilibrium ◽  
Typical Composition

In order to obtain essential information on the formation process of the high-Tc phase in the Bi, Pb–Sr–Ca–Cu–O system, subsolidus phase equilibrium in the systems PbO(PbO2)–SrO–CuO and PbO(PbO2)–CaO–SrO has been studied, mainly by XRD analysis. A pseudoternary Pb–Sr–Cu–O solid solution was newly found. This solid solution has a wide solubility range including its typical composition Pb2.03Sr3Cu0.73O7.70. It has a hexagonal structure with lattice parameters a = 10.11 and c = 7.11 in AU. Composition dependences of the lattice parameters and the decomposition (incongruent melting) temperature of (Ca1−xSrx)2PbO4 solid solution are also reported.

A Study of Intermetallic Compound Development In Nickel-Tin Interfacial Zones

1984 ◽  
Vol 40 ◽  
Author(s):  
Charles W. Allen ◽  
Mark R. Fulcher ◽  
Amarjit S. Rai ◽  
Gordon A. Sargent ◽  
Albert E. Miller
Keyword(s):  
Phase Diagram ◽  
Intermetallic Compound ◽  
Thin Layer ◽  
Room Temperature ◽  
Equilibrium Phase ◽  
Equilibrium Phase Diagram ◽  
Nickel Surface ◽  
X Ray Diffraction ◽  
Intermetallic Formation ◽  
X Ray

AbstractInterdiffusion and intermetallic formation in Ni-Sn interfacial zones are examined by X-ray diffraction in samples prepared by electroplating of Sn at room temperature. For the case of plating directly onto electropolished nickel, only very sluggish formation of Ni3Sn4 was observed at 190 C. In contrast, when the nickel surface is chemicaly or chemically-abrasively activated prior to plating, a thin layer of Ni3Sn forms at the initial interface at room temperature, and subsequent annealing at 100 and 190 C produces all intermetallics predicted by the equilibrium phase diagram including Ni3Sn, indicating that the absence of Ni3Sn usually observed arises from its failure to nucleate.

Phase Equilibria and Glass Forming Ability in the Zr-Cu-Ni-Al System

2000 ◽  
Vol 644 ◽  
Author(s):  
Douglas J. Swenson ◽  
Sreenivas Bhattiprolu
Keyword(s):  
Phase Equilibria ◽  
Eutectic Reaction ◽  
Eutectic Point ◽  
Quaternary Alloy ◽  
Analysis Data ◽  
Glass Forming Ability ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Glass Forming ◽  
System Phase

AbstractThe constitution of the 66.67 at.% Zr isopleth of the Zr-Cu-Ni-Al quaternary system has been studied, utilizing X-ray diffraction and electron probe microanalysis to establish phase equilibria at 800°C, and differential scanning calorimetry to study the liquidus hypersurface. As would be expected in a four-component system, phase equilibria were found to be complex. However, it was determined that the isoplethal subsection Zr2Cu-Zr2Ni is pseudobinary, and subsequently a large portion of the quaternary isopleth is pseudoternary, comprising equilibria involving the phases Zr2Cu, Zr2Ni and Zr6NiAl2. Moreover, these three phases participate in a pseudoternary eutectic reaction: L → Zr2Cu + Zr2Ni + Zr6NiAl2 at 852°C. Utilizing the thermal analysis data, the composition of the eutectic point was estimated to lie very near that of the well-known bulk metallic glass forming alloy Zr65Cu17.5Ni10Al7.5. The compositional proximity of a “deep” eutectic valley to this quaternary alloy thus provides a thermodynamic rationale for its high glass forming ability.

scholarly journals Phase Formation, Microstructure and Mechanical Properties of Mg67Ag33 as Potential Biomaterial

Metals ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 461
Author(s):  
Konrad Kosiba ◽  
Konda Gokuldoss Prashanth ◽  
Sergio Scudino
Keyword(s):  
Mechanical Properties ◽  
Young’S Modulus ◽  
Young's Modulus ◽  
Equilibrium Phase ◽  
Antibacterial Properties ◽  
Equilibrium Phase Diagram ◽  
Compressive Yield Strength ◽  
X Ray ◽  
Fine Grained ◽  
Equilibrium Phases

The phase and microstructure formation as well as mechanical properties of the rapidly solidified Mg67Ag33 (at. %) alloy were investigated. Owing to kinetic constraints effective during rapid cooling, the formation of equilibrium phases is suppressed. Instead, the microstructure is mainly composed of oversaturated hexagonal closest packed Mg-based dendrites surrounded by a mixture of phases, as probed by X-ray diffraction, electron microscopy and energy dispersive X-ray spectroscopy. A possible non-equilibrium phase diagram is suggested. Mainly because of the fine-grained dendritic and interdendritic microstructure, the material shows appreciable mechanical properties, such as a compressive yield strength and Young’s modulus of 245 ± 5 MPa and 63 ± 2 GPa, respectively. Due to this low Young’s modulus, the Mg67Ag33 alloy has potential for usage as biomaterial and challenges ahead, such as biomechanical compatibility, biodegradability and antibacterial properties are outlined.

scholarly journals Reduction of titanium oxide in the presence of nickel by nonequilibrium hydrogen gas

2009 ◽  
Vol 24 (7) ◽  
pp. 2391-2399 ◽  
Author(s):  
Hidehiro Sekimoto ◽  
Tetsuya Uda ◽  
Yoshitaro Nose ◽  
Shigeo Sato ◽  
Hiroaki Kakiuchi ◽  
...  
Keyword(s):  
Low Temperature ◽  
Relaxation Process ◽  
Reduction Potential ◽  
Hydrogen Plasma ◽  
Equilibrium Phase ◽  
Hydrogen Gas ◽  
X Ray Diffraction ◽  
Energy Process ◽  
X Ray ◽  
The Difference

We investigated the reduction of TiO2 in the presence of Ni by nonequilibrium hydrogen gas, including low-temperature hydrogen plasma at 800 °C and supercooled monatomic hydrogen at 1000 °C. TiO2 was reduced to Ti2O3, which is not in equilibrium phase, by low-temperature hydrogen plasma. The results of x-ray diffraction and energy dispersive x-ray analysis in experiments at 1000 °C indicate that the thermodynamical reduction potential of supercooled monatomic hydrogen is almost the same as atmospheric hydrogen gas. However, the wide Ti3O5 layer formed only in the case of the reduction at 1000 °C by supercooled monatomic hydrogen. With these experimental facts, we speculate that the reduction mechanism by nonequilibrium hydrogen consists of two steps; the releasing energy process and the relaxation process. We can explain the difference of reduction products by nonequilibrium hydrogen gas on the assumption of the rate of the relaxation process between 800 and 1000 °C.

scholarly journals Phase Equilibria in the In2O3-WO3 System

2002 ◽  
Vol 756 ◽  
Author(s):  
Annette P. Richard ◽  
Doreen D. Edwards
Keyword(s):  
Phase Equilibria ◽  
Binary Oxide ◽  
X Ray Diffraction ◽  
Subsolidus Phase ◽  
X Ray ◽  
Temperature Range ◽  
Oxide Phases ◽  
Phase Relationships

ABSTRACTThe subsolidus phase relationships in the In2O3-WO3 system at 800 – 1400°C were studied by X-ray diffraction. Two binary oxide phases – In2(WO4)3 and In6WO12 – are stable in air over the temperature range of 800 – 1200°C. Preferential volatilization of WO3 prevented the determination of phase equilibria above 1300°C.

Phase equilibria in the BaTiO3–La2TiO5–TiO2 system

1998 ◽  
Vol 13 (5) ◽  
pp. 1327-1334 ◽  
Author(s):  
Srečo Škapin ◽  
Drago Kolar ◽  
Danilo Suvorov ◽  
Zoran Samardžija
Keyword(s):  
Solid Solution ◽  
Electron Probe ◽  
Ternary Solid Solution ◽  
Secondary Phases ◽  
X Ray Diffraction ◽  
Binary Solid Solution ◽  
Subsolidus Phase ◽  
X Ray ◽  
Tie Lines ◽  
Scanning Electron

Subsolidus phase relations in the BaTiO3–La2TiO5–TiO2 part of the ternary BaO–La2O3–TiO2 system at 1300 °C in air were determined. The phases were characterized by x-ray diffraction, scanning electron microscopy, and electron probe wavelength dispersive spectroscopic microanalysis. A combination of techniques was employed because of insensitivity in detecting secondary phases by x-ray diffraction. The location and extent of Ba6−xLa8+2x/3Ti18O54 ternary solid solution 0.2(1) ⩽ x ⩽ 2.3(1) and Ba1−yLayTi1−y/4 (VTi)y/4O3 binary solid solution 0 ⩽ y ⩽ 0.3 at 1300 °C was established. Tie lines between various barium polytitanates with a sequence of Ba6−xLa8+2x/3Ti18O54 solid solution regions were determined.

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