Showing papers on "Binary system published in 1969"

Multiple phase formation in the binary system Nb2O5–WO3. VI. Electron microscopic observation and evaluation of non-periodic shear structures

Abstract: High-temperature Nb205 and a number of mixed Nb/W oxides with ordered shear structures have been examined by electron microscopy and electron diffraction. The generation of lattice images from the direct beam and one or more of the diffracted beams, hkl, affords a powerful method of studying inhomogeneities within their structures. The faults, which are planar, correspond in any one compound to regions of a second phase intergrown with it, and may be as small as half a unit cell in width a single fault, or a larger group representing a domain. The composition of these non-periodic regions differs from that of the host, and their presence will give rise to a composition range for the phase in which they occur.

PHASE EQUILIBRIA OF THE SYSTEM CaMgSi2O6-CaFe3+AlSiO6 IN AIR

Abstract: The phase equilibrium diagram for the system CaMgSiO2O6-CaFe3+AlSiO6 (abbreviated Fp) has been determined in air. It has been found that a complete series of clinopyroene solid solutions with a minimum at 1265°C and Di52.5 Fp47.5 is formed in the system. The unitcell dimensions and refractive indices change lineally with increase of Fp content. The diopside-rich side of this system (Di0-Di54) behaves like binary system. However, the Fp-rich side is more complicate, because the system is a part of a six-component system Fe-O-CaO-MgO-Al2O3-SiO2 The clinopyroxene solid solution which includes more than 46 mol percent Fp melts incongruently to magnetitess+liquid+gas, magnetitess+X+liquid+gas (X: unknown phase), or X+liquid+gas, respectively, with melting intervals.

The binary system CaO-Ta2O5☆

Abstract: A phase diagram for the CaO-Ta2O5 binary system has been plotted from results obtained using sub-solidus sintering, differential thermal analysis, hot-stage microscopy and an iridium-strip furnace. The compound CaO.2Ta2O5 melts incongruently at 1730 °C and the compounds α-CaO.Ta2O5 and 2CaO.Ta2O5 melt congruently at 1958 ° and 1896 °C, respectively. The α φ β CaO.Ta2O5 polymorphic transition occurs at 1558 ± 5 °C. X-ray data are given for two previously unreported calcium tantalates having the stoichiometric compositions 4CaO.Ta2O5 and 5CaO.Ta2O5, respectively. These two compounds formed a solid-solution area in the phase diagram at temperatures above 1590 °C and this single-phase region is postulated to terminate at 1990 °C, i.e., the incongruent melting point of 4CaO.Ta2O5.

Thermal Conductivity of Mixtures in the Dense Gaseous State: The Methane-Carbon Dioxide System

Abstract: Experimental thermal conductivities were established for the methane–carbon dioxide system using a coaxial cylindrical cell. These measurements were carried out on pure methane, carbon dioxide, and three binary mixtures containing 0.755, 0.464, and 0.243 mole fraction of methane. The temperatures of this study ranged from approximately 60° to 160°C and pressures extended up to 10 000 psi. The resulting thermal conductivities k for the dense gaseous state and the corresponding thermal conductivities of the dilute gas at atmospheric pressure, k*, for this binary system were used to produce the unique relationship for this system, (k − k*)λzc5 = 3.075 × 10−8[exp(1.203ρR) − exp(− 4.359ρR2)], where the thermal conductivity parameter, λ = M1/2Tc1/6 / Pc2/3. For the mixtures of this system, pseudocritical constants were used. This relationship was applied for the calculation of thermal conductivities which, when compared with corresponding experimental values, produced an average deviation of 2.24% for 220 exper...

Positron annihilation in Ni-Co alloys

Abstract: The binary system Ni-Co was studied by the positron-annihilation method. The value of the annihilation-spectrum peak was calculated from an approximate analytical formula and plotted against the cobalt concentration. In the plot two minima were observed corresponding to the ordered state and to the phase transition of the system Ni-Co, respectively.

Quasilattice Interpretation of the Thermodynamic Properties of Mixing of Binary Alkali‐Metal Systems

Abstract: Quasilattice theory was applied to heats of mixing in the six systems formed from the binary combinations of Na, K, Rb, and Cs. The alkali‐metal systems are particularly well suited for a critical test of the quasi‐crystalline assumption since the theoretical model for these systems is relatively simple and the thermodynamic data are fairly complex. Very good fits of the heat‐of‐mixing data were achieved by assuming that the larger atom in the binary system covered multiple sites on the quasilattice. The values of the empirically determined constants appear to fit the physical significance accorded to them by the quasilattice model. Values for the excess free energies of the Na–K system, calculated from the parameters of heat of mixing data, were in semiquantitative agreement with experimental data.

High Pressure Vapor-Liquid Equilibria for Binary System Containing C4-Hydrocarbons

Abstract: Vapor-liquid equilibria were measured for the isobutane-n-butane system at three temperatures ranging from 60°C to 100°C and for the system isobutane-isobutylene at 10.56atm. The results were correlated graphically by plotting the differences in the mole fractions of lighter hydrocarbons in the two phases as functions of the mole fraction in liquid phase. Throughout these experimentally investigated systems the observed difference between the compositions of coexisting phases was markedly less than that predicted by Raoult's law.For the isobutane-n-butane system, introducing the fugacity coefficients calculated from Black's equation of state, the behavior of the liquid phase was found almost ideal.

The use of thermodynamic properties of metal-gas systems as reduced-pressure standards

Abstract: Thermodynamic properties of erbium hydrogen binary system evaluated for use as low pressure standard

Thermodynamics of Titanium Alloys. III. The Titanium-Molybdenum System.

Abstract: : The activity of titanium in titanium-molybdenum alloys containing from 30 to 100 at.% titanium was measured using the triple Knudsen cell technique. The binary system shows positive deviation from ideality. The regular solution parameter, independent of temperature and composition, was determined to be Omega = 2.9 plus or minus 0.7 kcal/mol. This value agrees quite well, with values calculated from the phase diagram, and with those obtained from theoretical calculations. (Author)