Zu den Phasenverhältnissen im System V/Nb/O, III Die Koexistenzbeziehungen der Mischkristallreihe V1−x-NbxO2 zu den binären und ternären Phasen der Subsysteme VO2/NbO2/V2O3 und VO2/NbO2/V2O 5/Nb2O5 / The Phase Relations in the System V/Nb/O , III Coexistance Relations of Mixed Crystals V1−x-NbxO2 to the Binary and Ternary Phases of Subsystems VO2/NbO2/V2O3 und VO2/NbO2/V2O 5/Nb2O5

1997 ◽  
Vol 52 (10) ◽  
pp. 1155-1164
Author(s):  
F. von Woedtke ◽  
L. Kirsten ◽  
H. Oppermann
Keyword(s):  
Phase Diagram ◽  
Solid State ◽  
Ternary System ◽  
Chemical Transport ◽  
Phase Relations ◽  
Mixed Crystals ◽  
Solid State Reactions ◽  
Temperature Range

Mixed crystals V1−XNbXO2 exist about the whole area of quasibinary line VO2-NbO2. The phase relations between these compositions VO2-NbO2 and the binary and ternary phases of the described subsystems were cleared using chemical transport reactions (CTR) and solid state reactions. A more precise phase diagram of the ternary system V/Nb/O is given for the temperature range of 900 - 1000°C.

Untersuchungen zum ternären System Bi/Te/O, III. Bestimmung thermodynamischer Daten der ternären Verbindungen/Investigations on the Ternary System Bi/Te/O,III. Determination of Thermodynamic Data of Ternary Compounds

1999 ◽  
Vol 54 (2) ◽  
pp. 252-260 ◽  
Author(s):  
P. Schmidt ◽  
C. Hennig ◽  
H. Oppermann
Keyword(s):  
Solid State ◽  
Ternary System ◽  
Thermodynamic Data ◽  
Phase Relations ◽  
Solid State Reactions ◽  
Enthalpies Of Formation ◽  
Ternary Compounds ◽  
Heats Of Solution

The phase relations in the ternary system Bi/Te/O have been determined in previous studies by solid state reactions. Thermodynamical data have now been obtained for the pertinent equilibria. The heats of solution of Bi2O3, Bi12TeO20, Bi10Te2O19, Bi16Te5O34, Bi2TeO5, Bi2Te2O7, Bi2Te4O11 and TeCl4 were determined in 4N HCl. From these the enthalpies of formation of bismuth tellurites at 298 K have been derived:⊿H°b (Bi12TeO20, f, 298) = -901,6 ± 8 kcal/mol,⊿H°b (Bi10Te2O19, f, 298) = -856,1 ± 9 kcal/mol,⊿H°b (Bi16Te5O34, f, 298) = -1519,5 ± 17 kcal/mol,⊿H°b (Bi2TeO5, f, 298)= -222,8 ± 3 kcal/mol,⊿H°b (Bi2Te2O7, f, 298)= -299,4 ± 4 kcal/mol,⊿H°b (Bi2Te4O11, f, 298)= -448,2 ± 7 kcal/mol.

Phasenbeziehungen und Chemischer Transport der Verbindungen im ternären System Re/Mo/O / Phase Relations and Chemical Transport of the Compounds in the Ternary System Re/Mo/O

1998 ◽  
Vol 53 (4) ◽  
pp. 397-404 ◽  
Author(s):  
J. Feller ◽  
H Oppermann ◽  
R Kucharkowski ◽  
S Däbritz
Keyword(s):  
Ternary System ◽  
Transport Mechanism ◽  
Mixed Oxides ◽  
Chemical Transport ◽  
Phase Relations ◽  
Mixed Crystals ◽  
Thermodynamic Calculations ◽  
Powder Samples ◽  
O Phase

In the ternary system Re/Mo/O four series of mixed oxides have been prepared by heating of powder samples and by transport reactions. The series are derived from the oxides ReO2, MoO2, γ-Mo4O11 und η-Mo4-O11 and have compositions Re1-xMoxO2 (0 < x < 0.37), Mo1-yReyO2 (0 < y < 0.42),γ -Mo4-z1Rez1O11 (0 < z1 < 1), and η-Mo4-z2Rez2O11 (0 < z2 < 1). Contributions to the understanding of the transport mechanism were obtained from thermodynamic calculations. The composition of the mixed crystals obtained have been determined by EPMA and ICP-AES.

Untersuchungen zum ternären System Bi/Te/O, II. Thermisches Verhalten und Koexistenzbeziehungen von Bi2O2Te/Investigations of the Ternary System Bi/Te/O, II. The Thermal Behaviour and the Relations of Phase Coexistences of Bi2O2Te

1997 ◽  
Vol 52 (12) ◽  
pp. 1461-1466 ◽  
Author(s):  
P. Schmidt ◽  
O. Bosholm ◽  
H. Oppermann
Keyword(s):  
Solid State ◽  
Ternary System ◽  
Thermal Behaviour ◽  
Total Pressure ◽  
Chemical Transport ◽  
Solid State Reactions ◽  
Pressure Measurements ◽  
Pseudobinary System ◽  
X Ray ◽  
Solid Phases

Abstract The phase Bi2O2Te exists in the pseudobinary system Bi2O3/Bi2Te3. The thermal behaviour of Bi2O2Te was determined by DTA and X-ray analysis: The phase exists up to 620 °C and decomposes into the solid phases Bi12TeO20, Bi10Te2O19 [1] and liquid BiTe. The relations of the phase coexistences in the pseudobinary system and in the ternary area Bi2O3/TeO2/Bi2Te3/Te were investigated by solid state reactions, chemical transport reactions, and by total pressure measurements.

Solid State Electrochemical Study of Phase Equilibria and Thermodynamics of the Ternary System Y-Fe-O at Elevated Temperatures

1979 ◽  
Vol 34 (4) ◽  
pp. 430-436 ◽  
Author(s):  
W. Piekarczyk ◽  
W. Weppner ◽  
A. Rabenau
Keyword(s):  
Phase Diagram ◽  
Solid State ◽  
Ternary System ◽  
Phase Equilibria ◽  
Elevated Temperatures ◽  
Free Energies ◽  
Ternary Compounds ◽  
Temperature Range ◽  
The Third ◽  
Galvanic Cell Technique

A solid state galvanic cell technique has been employed to determine the phase diagram of the ternary system Y-Fe-O in the temperature range from 900 to 1250 °C. Only electrical quantities need to be measured and the samples do not have to be quenched. YFeO3 and Y3Fe5O12 exist over the entire temperature range, whereas the third ternary compound YFe2O4-x is only thermodynamically stable above 1010 ± 9 °C. Above 1078 ± 15 °C YFe2O4-x comes into equilibrium with Y2O3.With the same experimental arrangement the standard Gibbs free energies of formation ⊿G f0 of the ternary compounds YFeO3, Y3Fe5O12 and YFe2O4 have been determined to be -1366.0 + 0.2525 X T kJ/mol (1173 ≦ T [K] ≦ 1523), - 4912.2 +0.9990 X T kJ/mol (1173≦T[K] ≦ 1523) and -1615.9 + 0.3068 x T kJ/mol (1283≦T[K] ≦ 1523) as functions of the temperature, respectively

scholarly journals The use of ternary phase diagram sections in solid-state reactions involving TiC formation

1985 ◽  
Vol 16 ◽  
pp. 179-184 ◽  
Author(s):  
P RAMAEKERS ◽  
F VANLOO ◽  
G BASTIN ◽  
R METSELAAR
Keyword(s):  
Phase Diagram ◽  
Solid State ◽  
Ternary Phase ◽  
Ternary Phase Diagram ◽  
Solid State Reactions

Solid-state Reactions and Phase Relations in the Ti-Si-O System at 1373 K

1995 ◽  
Vol 78 (2) ◽  
pp. 313-322 ◽  
Author(s):  
Joseph I. Goldstein ◽  
Seung K. Choi ◽  
Frans J. J. Loo ◽  
Guillaume F. Bastin ◽  
Rudi Metselaar
Keyword(s):  
Solid State ◽  
Phase Relations ◽  
Solid State Reactions

Zur Chemie von Mischphasen in komplexen Zustandsdiagrammen Das System Bi2O3/Bi2Se3/Bi2Te3/Chemistry of Mixed Crystals in Complex Phase Diagrams The System Bi2O3/Bi2Se3/Bi2Te3

2000 ◽  
Vol 55 (7) ◽  
pp. 627-637 ◽  
Author(s):  
P. Schmidt ◽  
H. Oppermann
Keyword(s):  
Phase Diagram ◽  
Solid Solution ◽  
Phase Diagrams ◽  
Thermodynamic Modeling ◽  
Solid Solutions ◽  
Thermodynamic Data ◽  
Phase Relations ◽  
Mixed Crystals ◽  
Complex Phase ◽  
Quaternary Solid Solution

Abstract Pseudoternary System Bi2O3/Bi2Se3/Bi2Te3, Phase Diagram, Thermodynamic Data The phase diagram of the pseudoternary system Bi2O3/Bi2Se3/Bi2Te3 is found to include a quaternary solid solution Bi2O2 (TexSe1-x) and ternary, intermetallic mixed crystals Bi2(TexSe1-x)3. Using thermodynamic modeling of the solid solutions it is possible to calcu­ late complex heterogeneous equilibria between all phases of this phase diagram. As a result we can thermodynamically describe the observed phase relations:Bi2(TexSe1-x)3 ⊿H°m(298) = 0; ⊿S°m(298) = R[xlnx + (1-x)ln(1-x)]Bi2O2(TexSe1-x) ⊿H°m(298) = Ω · x(1-x); O⊿S°m(298) = R/4 [xlnx + (1-x)ln(1-x)]Ω = 0,6 kcal/mol

scholarly journals Early stages of solid state reactions: insights from micro-XRD and XAS

2014 ◽  
Vol 70 (a1) ◽  
pp. C1519-C1519
Author(s):  
Serena Tarantino ◽  
Paolo Ghigna ◽  
Elisabetta Achilli ◽  
Sonia Pin ◽  
Michele Zema ◽  
...  
Keyword(s):  
Phase Diagram ◽  
Solid State ◽  
Equilibrium Phase ◽  
Experimental System ◽  
Equilibrium Phase Diagram ◽  
Solid State Reactions ◽  
Reactive System ◽  
X Ray ◽  
Early Stages ◽  
Intermediate Phases

The mechanism of a solid state reaction in its early stages can be explored by investigating the time evolution of a model reactive system made of a thin layer of one reagent deposited onto a single crystal slab of the other reagent. Insights can be retrieved by comparing results at both local and long length scales obtained with films of different thicknesses and deposited onto different crystal orientations. In particular, reaction between ZnO and Al2O3has been chosen, as the spinel-forming reactions have been and still remain a model experimental system for investigating solid state reactions and because in the ZnO/Al2O3phase diagram, spinel is the only stable compound. The reaction initial steps have been investigated by using synchrotron X-ray diffraction, atomic force microscopy and X-ray absorption spectroscopy at the Zn-K edge starting from zincite films deposited onto (110)-, (012)-, (001)-oriented corundum single crystals [1,2]. The reaction eventually yields ZnAl2O4spinel but via a complex mechanism involving side and intermediate non-equilibrium compounds that do not appear in the equilibrium phase diagram of the pseudo-binary system. Spinel, when occurs, is polycrystalline at the end but initially forms with a few preferred orientations. Intermediate phases form before and in parallel with the growth of the spinel. Their number, composition, structure and kinetic role strongly depend on substrate orientation and film thickness. A more detailed understanding of the reactivity can be inferred by comparing EXAFS results to those of grazing incidence diffraction experiments of the films deposited on the (001) face of Al2O3and heat-treated at 10000C for different lengths of time. Information on the structure of the intermediate phases is given and results are discussed by comparing different films thickness to clarify the role of interfacial free energy and crystallographic orientation.

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