Development of liquidus thermobarometer for the simulation of equilibrium olivine-melt

A system of equations of the liquidus thermobarometer of olivine — silicate melt was obtained by processing the sample of 772 experimental equilibria of olivines with basic melts using methods of multidimensional statistics. Equations reproduce with small error experimental data in a wide range of basite compositions (from komatiites to dacites), temperatures from 1040 to 1500 ᵒС, pressures from 1 bar up to 30 kbar. Thermobarometer testing demonstrated that the deviations of the calculated liquidus temperature from the experimental one in most of the temperature range do not exceed ±3 ᵒC.

The influence of chemical composition on microstructure, hardness and electrical conductivity of Ag-Bi-In alloys at 100 °C

Considering possible applications and scarceness of literature data, Ag-Bi-In system was investigated in terms of microstructure, mechanical and electrical properties of ternary alloys from an isothermal section at 100oC. Based on the experimentally obtained results hardness and electrical conductivity of all ternary alloys from the ternary Ag-Bi-In system at 100oC were predicted. In addition, the selected isothermal section was further thermodynamically assessed and experimentally studied using scanning electron microscopy (SEM) with energy dispersive spectrometry (EDS), X-ray powder diffraction (XRD) analysis and light optical microscopy (LOM). Phase transition temperatures of alloys with overall compositions along vertical sections x(Ag)=0.5 as well as liquidus temperatures were experimentally determined by DTA. The experimentally obtained results were compared with literature data and with the results of thermodynamic calculation of phase equilibria based on CALPHAD method and corrected data for Ag-In binary system. Calculated liquidus projection, invariant equilibria and phase diagram of the Ag-Bi-In ternary system are presented as well.

Prediction of phase equilibria in the In-Sb-Pb system

Binary thermodynamic data, successfully used for phase diagram calculations of the binary systems In-Sb, Pb-Sb and In-Pb, were used for the prediction of the phase equilibria in the ternary In-Sb-Pb system. The predicted equilibrium phase diagram of the vertical Pb-InSb section was compared with the results of differential thermal analysis (DTA) and optical microscopy. The calculated phase diagram of the isothermal section at 300 ?C was compared with the experimentally (SEM, EDX) determined composition of phases in the chosen alloys after annealing. Very good agreement between the binary-based thermodynamic prediction and the experimental data was found in all cases. The calculated liquidus projection of the ternary In-Sb-Pb system is also presented.

Calculated melt and restite compositions of some Australian granites

ABSTRACTThe thermodynamic relations embodied in the Quasicrystalline Model of Burnham and Nekvasil (1986), as recently extended by the author, have been used to quantitatively assess the feldspar-quartz liquidus relations in two I-type (Jindabyne and Moruya) and two S-type (Bullenbalong and Dalgety) suites of Australian granites, using analytical data provided by B. W. Chappell and co-workers. Among the more notable results obtained from these calculations at a constant pressure of 5·0kbar and = 0·30 (≍2·8 wt% H2O), for purposes of comparison, are that: (1) felsic melts of remarkably uniform, but distinctive composition can be extracted from each suite, leaving solid residues in amounts up to 65 mol%; (2) all melts from both S-type suites have two feldspars plus quartz on their liquidii, whereas both I-type suites have only plagioclase plus quartz on their liquidii; (3) the total solid residue ranges from 27-63% in the Jindabyne suite, from 15–62% in the Moruya suite, from 30–65% in the Bullenbalong suite, and from 27–65% in the Dalgety suite; (4) liquidus temperatures of the S-type Bullenbalong and Dalgety melts are similar (856° and 860°C), reflecting similar feldspar compositions of An53, Or75 and An60, Or77, respectively; (5) liquidus temperatures of the I-type Jindabyne and Moruya melts, however, are distinctly different (950° and 894°C), reflecting correspondingly different plagioclase compositions of An80 and An52; (6) the calculated liquidus plagioclase composition throughout a given suite is very uniform (±1%) and amounts to as much as 46% of the total rock; and (7) these calculated liquidus and residual plagioclase compositions are also the same, within the uncertainty of measurement, as those of the plagioclase crystal-cores determined optically by A. J. R. White. The only plausible explanation for this remarkable consanguinity in plagioclase liquidus, residue, and crystal-core compositions, hence liquidus temperatures, is that the bulk of the residue is restite, in accordance with the model of White and Chappell (1977). This explanation is corroborated by the very systematic variations in the amounts of individual restite minerals with respect to total restite contents. Accordingly, those members of each suite that contain more than 60% total restite probably closely represent the bulk composition of the source rock, which is dioritic or andesitic for the Jindabyne suite, tonalitic or dacitic for the Moruya suite, pelitic metagreywacke for the Bullenbalong suite, and feldspathic metagreywacke for the Dalgety suite. As a corollary, those members with less than 60% restite must have undergone melt-restite segregation (unmixing), probably during ascent and emplacement.