ChemInform Abstract: Phase Equilibria in the Hf-Ni-Sn Ternary System and Crystal Structure of the Hf2Ni2Sn Compound.

ChemInform ◽  
2010 ◽  
Vol 32 (27) ◽  
pp. no-no
Author(s):  
Yu. V. Stadnyk ◽  
L. P. Romaka
Keyword(s):  
Crystal Structure ◽  
Ternary System ◽  
Phase Equilibria

Phase Equilibria and Oxidation Behavior of C40 Disilicides in the Nb-Cr-Si System

2015 ◽  
Vol 1760 ◽  
Author(s):  
Nobuaki Sekido ◽  
Ryoma Aizawa ◽  
Shunkichi Ueno
Keyword(s):  
Crystal Structure ◽  
Phase Equilibrium ◽  
Ternary System ◽  
Phase Equilibria ◽  
Oxidation Resistance ◽  
Oxidation Behavior ◽  
Phase Boundaries ◽  
Compositional Homogeneity ◽  
Poor Oxidation Resistance

ABSTRACTThe phase equilibrium and oxidation behavior of the disilicides that form in the Nb-Cr-Si ternary system have been investigated. Although NbSi2 and CrSi2 both exhibit a C40 crystal structure, they form separate ranges of compositional homogeneity in the ternary system. Their phase boundaries at 1300 °C have been experimentally determined in this study. The binary NbSi2 exhibited poor oxidation resistance, showing pest-like behavior during oxidation at temperature above 800 °C. In contrast, the alloys containing Cr showed much better oxidation resistance up to 1200 °C.

scholarly journals Tl2Se–TlInSe2–Tl4P2Se6 QUASITERNARY SYSTEM

2019 ◽  
Vol 85 (2) ◽  
pp. 101-110
Author(s):  
Igor Barchiy ◽  
Valeriya Tovt ◽  
Michal Piasecki ◽  
Anatolii Fedorchuk ◽  
Artem Pogodin ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Ternary System ◽  
Phase Equilibria ◽  
Solid Solutions ◽  
Chemical Interaction ◽  
Structural Parameters ◽  
State Diagram ◽  
Complex Compounds ◽  
Perspective View ◽  
Quasiternary System

Complex chalcogenide compound are widely used as working elements for semiconductor optical technology, thermal generation, solar power. Special attention is paid to compounds of the M2P2Se6 type (M – Ag, Cu) which due to its layer crystal structure possess promising ferroelectric, thermoelectric and electro-optical properties. Heterovalent substitutions of cations 2М2+ ® 4M1+ in the composition of M2P2Se6 type compounds must leads to deformation of the crystal structure, changing in the value of the dipole moment and, accordingly, to change the electro-physical properties. The Tl2Se–In2Se3–“P2Se4” system characterized by the formation of intermediate complex compounds which melts congruently TlInSe2 (1023 К), Tl4P2Se6 (758 К), TlInP2Se6 (875 К) and TlIn5Se8 (melts incongruently L+In2Se3«TlIn5Se8 at 1029 К), In4(P2Se6)3 (formed by syntactic reaction at 880 К). Triangulation of the Tl2Se–In2Se3–“P2Se4” system was shown that then divided on secondary quasiternary systems, one of them is Tl2Se–TlInSe2–Tl4P2Se6. Phase equilibria in the Tl2Se – TlInSe2 – Tl4P2Se6 quasiternary system were studied using classical methods of physicochemical analysis DTA (chromel-alumel thermocouple, with an accuracy of ±5 K), XRD (DRON-3-13 diffractometer, Cu Ka radiation, Ni filter, Guinier Huber G670 diffractometer, CuKα1 radiation), MSA (metallographic microscope Lomo Metam R1) in combination with the simplex method of mathematical modeling of phase equilibria in multi-component systems. Crystal structure calculation was carried out with program WinCSD. Investigation of physical-chemical interaction allowed to constructed perspective view of phase state diagram and liquidus surface projection of the Tl2Se–TlInSe2–Tl4P2Se6 ternary system. In the ternary system formed the boundary solid solution: a- on the basis of Tl2Se, b- on the basis of TlInSe2, g-, d-, e- on the basis of ltm-, mtm- and htm-Tl4P2Se6 (ltm, mtm, htm – low, middle and high temperature modification, respectively). The liquidus of the ternary system consists of primary crystallization areas: Tl2Se-е1-Е1-е2-Tl2Se (a phase), TlInSe2-е3-U2-U1-E1-TlInSe2 (b phase), m1-U1-E1-e2-m1 (g phase), m2-U2-U1-m1-m2 (d phase) and Tl4P2Se6-e5-U2-m2-Tl4P2Se6 (ε phase). The Tl2Se–TlInSe2–Tl4P2Se6 quasiternary system is characterized by the processes: monovariant eutectic L«htmTl4P2Se6+TlInSe2 (e5-U2, 776-693 К), monovariant eutectic L«Tl2Se+TlInSe2 (e1-Е1, 614-539 К), monovariant eutectic L«Tl2Sе+ltmTl4P2Se6 (e2-Е1, 610-539 К); monovariant peritectic L+mtmTl4P2Se6«ltmTl4P2Se6 (m1-U1, 640-620 К); monovariant peritectic L+htmTl4P2Se6« mtmTl4P2Se6 (m2-U2, 747-693 К); monovariant peritectic L+mtmTl4P2Se6«TlInSe2 (U2-U1, 693-620 К); monovariant peritectic L+ltmTl4P2Se6«TlInSe2 (U1-E1, 620-539 К). Lines of the monovariant equilibria are crossed in three point: U2 – invariant peritectic process L+htmTl4P2Se6«TlInSe2+mtmTl4P2Se6 (12 mol.% Tl2Se, 20 mol.% TlInSe2, 68 mol.% Tl4P2Se6, 693 К), U1 – invariant peritectic process L+mtmTl4P2Se6«TlInSe2+ltmTl4P2Se6 (38 mol.% Tl2Se, 9 mol.% TlInSe2, 53 mol.% Tl4P2Se6, 620 К), E1 – invariant eutectic process L « Tl2Se+TlInSe2+ltmTl4P2Se6 (47 mol.% Tl2Se, 7 mol.% TlInSe2, 46 mol.% Tl4P2Se6, 539 К). New complex compounds were not observed in the ternary system. Limited solid solutions on the basis of TlInSe2, Tl4P2Se6 initial compounds are not up to 5–8 mol%. Crystal-structure studies of Tl2Se, TlInSe2 and Tl4P2Se6 complex chalcogenides were carried out by a powder method, refinement of the structural parameters – by the Rietveld method. The lattice parameters are: Tl2Se – Р4/n, а=8,540; с=12,380 Å, TlInSe2 – I4/mcm, a=8.064, c=6.833 Å, Tl4P2Se6 – P121/c1, a=12.239, b=9.055, c=12.328 Å, b=98.83. Crystal-chemical analysis of the compounds showed that they are characterized by a mixed ion-covalent type of chemical bond. During the transition from the binary Tl2Se to TlInSe2 ternary compound the covalent component of the In–Se bond is enhanced, the opposite change is observed for Tl4P2Se6, an increase in the ion component of the Tl–Se bond. The study of the mechanisms of formation of solid solutions showed that with the reciprocal solubility of the TlInSe2, Tl4P2Se6 ternary compounds characterized by the formation of substitution structure, the dissolution of Tl2Se in ternary selenides follows the substitution and subtraction mechanism.

The ternary system: Aluminum–iron–praseodymium

1991 ◽  
Vol 6 (1) ◽  
pp. 53-56 ◽  
Author(s):  
H. Klesnar ◽  
P. Rogl
Keyword(s):  
Crystal Structure ◽  
Ternary System ◽  
Phase Equilibria ◽  
Ternary Phase ◽  
Type Structure ◽  
Two Phase ◽  
X Ray ◽  
Rich Liquid ◽  
Random Substitution ◽  
Homogeneous Regions

Phase equilibria in the ternary system Pr–Fe–Al have been established in an isothermal section at 800 °C from room temperature x-ray powder diffraction analysis of about 50 alloys, which were melted, annealed at 800 °C, and quenched. Phase equilibria are characterized by the formation of rather extended homogeneous regions, i.e., by a random substitution of Fe/Al in Pr(Al1−xFex)2, 0 ≤ x ≤ 0.15, in Pr2(Fe1−xAlx)17, 0 ≤ x ≤ 0.65, as well as by the formation of at least four ternary compounds. Whereas the existence of PrFe4Al8 with the CeMn4Al8-type structure has been confirmed, there were no indications for a compound “PrFe6Al6” earlier claimed to crystallize with the ThMn12-type structure. Pr6(Fe1−xAlx)14, 0.16 ≤ x ≤ 0.36 with a homogeneous region parallel to the Fe–Al binary, was found to be isotypic with the La6Co11Ga3-type of structure. Pr-rich alloys are liquid at 800 °C, and all the alloys Pr2(Fe1−xAlx)17 with aluminum concentrations less than 5 at.% Al (x ∼ 0.07) enter a two-phase equilibrium with the Pr-rich liquid. At temperatures below 800 °C, alloys with compositions close to 30 at.% Pr and 5 at.% Al show a further ternary phase on solidification, whose crystal structure is related to the La6Co11Ga3-type. PrFe2Al8 is a new representative of the CeFe2Al8-type structure. The crystal structure of the ternary compound richest in Al, PrFe2Al10, has not been solved yet.

scholarly journals Phase equilibria in Co−Al−Re ternary system at 1100 and 1300 °C

2021 ◽  
Vol 31 (6) ◽  
pp. 1740-1747
Author(s):  
Ling-ling LI ◽  
Jin-bin ZHANG ◽  
Yue-chao CHEN ◽  
Shui-yuan YANG ◽  
Cui-ping WANG ◽  
...  
Keyword(s):  
Ternary System ◽  
Phase Equilibria

Phase equilibria of the La–Ni–Cu ternary system at 673 K: Thermodynamic modeling and experimental validation

Calphad ◽  
2012 ◽  
Vol 36 ◽  
pp. 8-15 ◽  
Author(s):  
Xuehui An ◽  
Qian Li ◽  
Jieyu Zhang ◽  
Shuanglin Chen ◽  
Ying Yang
Keyword(s):  
Ternary System ◽  
Phase Equilibria ◽  
Thermodynamic Modeling ◽  
Experimental Validation
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