Phase transformations and thermal conductivity of the In-Ag alloys

Phase transformations and thermal conductivity of three In-Ag alloys with 5, 15, and 45 wt.% of Ag were experimentally investigated in the present work. Phase transition temperatures were measured using differential scanning calorimetry (DSC). DSC heating scans were compared with the equilibrium and non-equilibrium solidification paths, calculated by using optimized thermodynamic parameters from literature and calculation of phase diagrams (CALPHAD) method.  The flash method was employed for the determination of thermal diffusivity and thermal conductivity of the investigated alloys in the temperature range from 25 to 100 °C. It has been found that an increase in silver content does not lead to an increase in the thermal conductivity of the investigated alloys. Thermal conductivities for all three investigated In-Ag alloys slightly decrease with temperature increasing

Planning and Multicriterial Optimization OD Design Business Processed

This paper presents importancy of reingenering, designing and optimization of processes and products to enhance business quality as well as to reduce costs and losts. The approch is presented by PEPSY (Product Development Planning System) tool, providing support for the restructuring and optimization of business processes surpassing the functional scope of commercially available tools. The approach sets the further goal of employing the business models generated to perform a multicriterial optimization process 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

Thermodynamics and phase diagram calculation of some sections in the Ag–Bi–Sn system

The thermodynamic properties and characteristic phase diagrams of some sections in the Ag–Bi–Sn system were calculated. The thermodynamic functions, such as Gibbs excess energy, activity and enthalpy of formation, were calculated using the RKM model and compared with experimental data reported in the literature. Iso-activity diagrams for all three components at 900 K have been constructed. The calculated phase diagrams of the vertical sections Sn–AgBi, Ag–BiSn and Bi–AgSn, obtained using the ThermoCalc program, were compared and confirmed with the results of DTA measurements from the present work

Kinetics and mechanism of As2S2 oxidation

The kinetics of realgar (As2S2) oxidation was studied under isothermal and non-isothermal conditions. The obtained values of the activation energy indicate that the process occurs in the kinetic domainwith the realgar particles being converted to As2O3 and As4O6 (g). The very fast reaction rates were limited by the chemical reaction. The kinetic equation was found to be: –ln (1–a) = 4.56 × 103 × e(–8780/T) × t. The proposed reaction mechanism and chemical transformation investigated by ICP–AES, EDXRF and thermal analysis are discussed