Phase equilibria in the system ZnCl2 + KI

1974 ◽  
Vol 27 (1) ◽  
pp. 35 ◽  
Author(s):  
AJ Easteal ◽  
PJ O'Rourke
Keyword(s):  
Phase Separation ◽  
Phase Equilibria ◽  
Glass Transitions ◽  
Heating Rates ◽  
Glass Transition Temperatures ◽  
X Ray ◽  
Critical Composition ◽  
Congruently Melting ◽  
Nitrogen Yields ◽  
Liquidus Temperatures

Phase equilibria in the ZnCl2+KI system have been investigated by differential thermal analysis (DTA), and by examination by X-ray powder diffraction of solidified melts. The system evidently behaves as a simple binary, and three congruently melting compounds are formed, viz. 2KI.ZnCl2, 2KI.3ZnCl2 and KI.4ZnC12. Supercooled mixtures from c. 60-90 mole % ZnCl2 visibly phase separate at temperatures for the most part about 30K below the liquidus temperatures, and the phase separation temperatures have been determined by DTA. The composition limits of the metastable immiscibility dome have not been established, but the region of phase separation extends at least to mixtures containing as little as 53 mole % ZnCl2. The critical composition is approximately 80 mole % ZnCl2, and the critical temperature 470 K. Quenching of melts containing 34-100 mole % ZnCl2, in liquid nitrogen, yields glasses. In the region 34-43 mole % ZnCl2 the glasses are partly crystallized. Glass transition temperatures for the wholly glassy mixtures have been evaluated from DTA traces, with heating rates in the range 0.11-0.25 K s-1. Two glass transitions have been observed for mixtures of composition 53-75 mole % ZnCl2.

Solid–Liquid Phase Equilibria for the Ternary Systems V2O5–Na2O–Fe2O3, V2O5–Na2O–Cr2O3, and V2O5–Na2O–MgO

1973 ◽  
Vol 51 (7) ◽  
pp. 1032-1040 ◽  
Author(s):  
R. C. Kerby ◽  
J. R. Wilson
Keyword(s):  
Liquid Phase ◽  
Phase Equilibria ◽  
Oxygen Partial Pressure ◽  
Partial Pressure ◽  
Binary Systems ◽  
Ternary Systems ◽  
X Ray ◽  
Equilibrium Relationships ◽  
Solid Liquid ◽  
Liquidus Temperatures

The phase equilibrium relationships of several vanadate systems have been studied by a combination of differential thermal analysis (DTA) and X-ray powder diffraction methods. All systems studied were eutectic in nature. The liquidus temperatures of the sodium vanadates were found to depend on the oxygen partial pressure for sodium oxide concentrations between 1.0 and 36 mol%. This effect was not observed for the ferric vanadate, chromic vanadate or magnesium vanadate systems. The solid–liquid phase equilibria for the ternary vanadate systems V2O5–Na2O–Fe2O3, V2O5–Na2O–Cr2O3, and V2O5–Na2O–MgO were measured by determining the temperature–composition data for various quasi-binary systems within each ternary system. Liquidus temperatures between 500 and 700 °C were found for those compositional ranges containing greater than 40 mol% V2O5 and between 10 and 60 mol% Na2O. The liquidus temperatures decreased with increasing oxygen partial pressure over much of the same compositional range.

scholarly journals Kinetically controlled glass transition measurement of organic aerosol thin films using broadband dielectric spectroscopy

2018 ◽  
Vol 11 (6) ◽  
pp. 3479-3490 ◽  
Author(s):  
Yue Zhang ◽  
Shachi Katira ◽  
Andrew Lee ◽  
Andrew T. Lambe ◽  
Timothy B. Onasch ◽  
...  
Keyword(s):  
Glass Transition ◽  
Dielectric Spectroscopy ◽  
Organic Aerosols ◽  
Transition Temperatures ◽  
Glass Transitions ◽  
Relaxation Rates ◽  
Heating Rates ◽  
Glass Transition Temperatures ◽  
Broadband Dielectric Spectroscopy ◽  
Kinetically Controlled

Abstract. Glass transitions from liquid to semi-solid and solid phase states have important implications for reactivity, growth, and cloud-forming (cloud condensation nuclei and ice nucleation) capabilities of secondary organic aerosols (SOAs). The small size and relatively low mass concentration of SOAs in the atmosphere make it difficult to measure atmospheric SOA glass transitions using conventional methods. To circumvent these difficulties, we have adapted a new technique for measuring glass-forming properties of atmospherically relevant organic aerosols. Aerosol particles to be studied are deposited in the form of a thin film onto an interdigitated electrode (IDE) using electrostatic precipitation. Dielectric spectroscopy provides dipole relaxation rates for organic aerosols as a function of temperature (373 to 233 K) that are used to calculate the glass transition temperatures for several cooling or heating rates. IDE-enabled broadband dielectric spectroscopy (BDS) was successfully used to measure the kinetically controlled glass transition temperatures of aerosols consisting of glycerol and four other compounds with selected cooling and heating rates. The glass transition results agree well with available literature data for these five compounds. The results indicate that the IDE-BDS method can provide accurate glass transition data for organic aerosols under atmospheric conditions. The BDS data obtained with the IDE-BDS technique can be used to characterize glass transitions for both simulated and ambient organic aerosols and to model their climate effects.

Bulk standards for low-temperature biological x-ray microanalysis

1984 ◽  
Vol 42 ◽  
pp. 282-283
Author(s):  
P. Echlin ◽  
M. McKoon ◽  
E.S. Taylor ◽  
C.E. Thomas ◽  
K.L. Maloney ◽  
...  
Keyword(s):  
Phase Separation ◽  
Low Temperature ◽  
Analytical Method ◽  
Salt Solutions ◽  
Absolute Concentration ◽  
Cooling Process ◽  
X Ray ◽  
The Absolute ◽  
Analytical Procedures ◽  
Electrical Conductors

Although sections of frozen salt solutions have been used as standards for x-ray microanalysis, such solutions are less useful when analysed in the bulk form. They are poor thermal and electrical conductors and severe phase separation occurs during the cooling process. Following a suggestion by Whitecross et al we have made up a series of salt solutions containing a small amount of graphite to improve the sample conductivity. In addition, we have incorporated a polymer to ensure the formation of microcrystalline ice and a consequent homogenity of salt dispersion within the frozen matrix. The mixtures have been used to standardize the analytical procedures applied to frozen hydrated bulk specimens based on the peak/background analytical method and to measure the absolute concentration of elements in developing roots.

scholarly journals Stable and Metastable Phase Equilibria Involving the Cu6Sn5 Intermetallic

2021 ◽  
Author(s):  
A. Leineweber ◽  
M. Löffler ◽  
S. Martin
Keyword(s):  
Phase Equilibria ◽  
Electron Backscatter Diffraction ◽  
Metastable Phase ◽  
Stable Phase ◽  
X Ray Diffraction ◽  
X Ray ◽  
Heat Treated ◽  
Ordered Phases ◽  
Backscatter Diffraction ◽  
Kinetics Of

Abstract Cu6Sn5 intermetallic occurs in the form of differently ordered phases η, η′ and η′′. In solder joints, this intermetallic can undergo changes in composition and the state of order without or while interacting with excess Cu and excess Sn in the system, potentially giving rise to detrimental changes in the mechanical properties of the solder. In order to study such processes in fundamental detail and to get more detailed information about the metastable and stable phase equilibria, model alloys consisting of Cu3Sn + Cu6Sn5 as well as Cu6Sn5 + Sn-rich melt were heat treated. Powder x-ray diffraction and scanning electron microscopy supplemented by electron backscatter diffraction were used to investigate the structural and microstructural changes. It was shown that Sn-poor η can increase its Sn content by Cu3Sn precipitation at grain boundaries or by uptake of Sn from the Sn-rich melt. From the kinetics of the former process at 513 K and the grain size of the η phase, we obtained an interdiffusion coefficient in η of (3 ± 1) × 10−16 m2 s−1. Comparison of this value with literature data implies that this value reflects pure volume (inter)diffusion, while Cu6Sn5 growth at low temperature is typically strongly influenced by grain-boundary diffusion. These investigations also confirm that η′′ forming below a composition-dependent transus temperature gradually enriches in Sn content, confirming that Sn-poor η′′ is metastable against decomposition into Cu3Sn and more Sn-rich η or (at lower temperatures) η′. Graphic Abstract

Cation distributions and possible phase separation inTl2Ba2CuO6+δfrom synchrotron powder x-ray diffraction

1995 ◽  
Vol 51 (18) ◽  
pp. 12747-12753 ◽  
Author(s):  
M. A. G. Aranda ◽  
D. C. Sinclair ◽  
J. P. Attfield ◽  
A. P. Mackenzie
Keyword(s):  
Phase Separation ◽  
X Ray Diffraction ◽  
X Ray ◽  
Cation Distributions

Structure of Microphase-Separated Silica/Siloxane Molecular Composites

1989 ◽  
Vol 171 ◽  
Author(s):  
Dale W. Schaefer ◽  
James E. Mark ◽  
David Mccarthy ◽  
Li Jian ◽  
C. -C. Sun ◽  
...  
Keyword(s):  
Phase Separation ◽  
Kinetic Studies ◽  
Organic Content ◽  
Small Particles ◽  
X Ray ◽  
Filled Elastomers ◽  
Polymeric Networks ◽  
Large Particles ◽  
Molecular Composites

ABSTRACTThe structure of several classes of silica/siloxane molecular composites is investigated using small-angle x-ray and neutron scattering. These filled elastomers can be prepared through different synthethic protocols leading to a range of fillers including particulates with both rough and smooth surfaces, particulates with dispersed interfaces, and polymeric networks. We also find examples of bicontinuous filler phases that we attribute to phase separation via spinodal decomposition. In-situ kinetic studies of particulate fillers show that the precipitate does not develop by conventional nucleation-and-growth. We see no evidence of growth by ripening whereby large particles grow by consumption of small particles. Rather, there appears to be a limiting size set by the elastomer network itself. Phase separation develops by continuous nucleation of particles and subsequent growth to the limiting size. We also briefly report studies of polymer-toughened glasses. In this case, we find no obvious correlation between organic content and structure.

scholarly journals Synchrotron X-ray In Situ Tomography of Thermally Induced Phase Separation of Polylactic Acid in 1,4-Dioxane Solution

2018 ◽  
Vol 18 (12) ◽  
pp. 7496-7503 ◽  
Author(s):  
Swann Gay ◽  
Brice Calvignac ◽  
Landry Ouanssi Kamtcheu ◽  
Thomas Beuvier ◽  
Elodie Boller ◽  
...  
Keyword(s):  
Phase Separation ◽  
Polylactic Acid ◽  
Dioxane Solution ◽  
Thermally Induced Phase Separation ◽  
Thermally Induced ◽  
X Ray
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