Wojciech Gierlotka

Thermodynamic descriptions of the Cu–Zn system

The thermodynamic behavior of the Ga–Li system is analyzed using the calculation of phase diagram technique. The liquid phase is modeled with the Redlich–Kister equation. The ordered intermetallic compound GaLi is thermodynamically described by a two sublattice model. The other compounds are treated as stoichiometric compounds. A set of self-consistent thermodynamic parameters is obtained. 2003 Acta Materialia Inc. Published by Elsevier Science Ltd. All rights reserved.

Thermodynamic Description of the Quaternary Ag-Cu-In-Sn System

Due to new regulations, the classic Sn-37Pb (wt.%) solder must be replaced by lead-free material. There are many alloys that could be used instead of this classic lead solder, including quaternary Ag-Cu-In-Sn alloy. The CALPHAD method was used for thermodynamic description of this quaternary system. Good agreement between calculation and available experimental information was found. Solidification of the promising lead-free solder Sn-1.5Ag-0.7Cu-9.5In (wt.%) was performed using the Scheil approach, and good agreement between this calculation and differential thermal analysis results was found. The obtained set of Gibbs energy functions can be used in the future for expanding the quaternary system to high-order ones.

Thermodynamic properties of liquid silver–indium–antimony alloys determined from e.m.f. measurements

Abstract The thermodynamic properties of liquid Ag–Sb–In alloys were determined using solid oxide galvanic cells with zirconia electrolyte. The following galvanic cells were employed: (I) Re + kanthal, Ag x − Sb ( 1 − x − y ) , In 2 O 3 / / ZrO 2 + ( Y 2 O 3 ) / / Ni O , Ni , Pt in the temperature range from 973 to 1200K. Thermodynamic properties of the liquid phase were described by the Redlich–Kister–Muggianu formula and the phase relations in the ternary system were calculated. The results of the calculations were compared with experimental data available from different literature sources.

Experimental Determination and Thermodynamic Modelingof the Sn-Rich Corner of the Ternary Ni-Pd-Sn PhaseDiagram at 250°C

The Sn-rich portion of the phase diagram for the Ni-Pd-Sn ternary system was preliminarily obtained by interpolation of the three constituent binary systems using the Muggianu method. Based on this proposition, 23 Ni-Pd-Sn alloys were prepared and annealed at 250°C. The annealed alloys were analyzed by scanning electron microscopy, electron probe microanalysis, electron backscatter diffraction, and x-ray diffraction. All the binaries adjacent to the Sn-rich corner (i.e., PdSn4, PdSn3, PdSn2, and Ni3Sn4) were found to have remarkable ternary solubility. The experimental results presented herein, together with a thermodynamic interpolation of the ternary system based on the results from the binary systems, were used to calculate the ternary phase diagram using the calculation of phase diagrams (CALPHAD) method. A substitution model was used to describe the Gibbs free energies of the liquid and solid solution phases, and a sublattice model was used to describe intermetallic compounds. A consistent set of thermodynamic parameters was obtained, ultimately leading to a better fit between the calculated results and the experimental data for this system.

Atomic Mobilities in the Ag-Cu-Sn Face-Centered Cubic Lattice

Knowledge of atomic mobilities is necessary to predict the evolution of microstructure. The theoretical description of atomic mobilities is connected to the chemical potentials of the components in a given phase. A new thermodynamic description of the quaternary Ag-Cu-In-Sn system was recently published, and it is clear that a new description of the mobilities is also necessary. Based on the available literature and using Dictra software, optimization of the mobility parameters of silver, copper, and tin in the face-centered cubic phase was carried out. The results were compared with relevant data from literature as well as with our own experimental results. Good agreement between calculations and experiment was obtained.

Thermodynamic properties of liquid silver-indium-tin alloys determined from emf measurements

Abstract The thermodynamic properties of liquid Ag – Sn – In alloys were determined using solid oxide galvanic cells with zirconia electrolyte. The following galvanic cells were employed: Re + kanthal, Agx – Iny – Sn(1−x−y),(In2O3)s.s//ZrO2 + (Y2O3)//NiO, Ni, Pt(I) in the temperature range from 973 to 1273 K, and in the range of indium mole fraction from 0.3 to 0.8. This limitation was imposed by the side reaction between tin in the liquid alloy and solid In2O3. It was also found that the liquid is in equilibrium with the solid solution of oxides. Calorimetric measurements of the heat of mixing were also carried out at constant temperature 1003 K and along one isopleth with XAg/XSn = 1/1. The thermodynamic properties of the liquid phase were described by the Redlich – Kister – Muggianu formula and the phase relations in the ternary system were calculated. The results of calculations were compared with the experimental data which are available from different literature sources.

Experimental Studies and Thermodynamic Assessment of Ternary Cu-Pd-Sn Phase Relations Focusing on the Sn-Rich Alloys

Recently, Pd surface finishes over Cu substrates have been widely used in microelectronic packaging to prevent pad oxidation before soldering and to improve the bondability with Cu wires. The interfacial reactions between these newly developed Pd-based substrates and Pb-free solders, particularly Sn-based solders, are of practical importance. To completely understand interfacial reactions and phase transformation phenomena, phase equilibrium information on solders, intermetallics, and substrate materials are required. In this study, the phase equilibria of the Cu-Pd-Sn ternary system at 200°C was investigated by scanning electron microscopy, electron probe microanalysis, and electron backscatter diffraction. Particular emphasis was placed on the Sn-rich corner of the isothermal section. To analyze the experimental results, a thermodynamic assessment was performed using the computer coupling of phase diagrams and thermochemistry method.

Thermodynamic properties of liquid copper–antimony–tin alloys determined from e.m.f. measurements

Abstract The thermodynamics properties of liquid Cu–Sn–Sb alloys were determined using solid-oxide galvanic cells with zirconia electrolyte:(1)Re+kanthal,Cux−Sby−Sn(1−x−y),SnO2//ZrO2+(Y2O3)//NiO,Ni,Pt in the temperature range from 998 to 1223 K. The Gibbs free energy of formation of pure solid SnO2 from pure elements was derived. Using electromotive force values measured for the cell with xSn = 1.0, the following temperature dependence was obtained:ΔGf,SnO20=−567903+200.33T(±1000J)[Jmol−1] Activities of tin were determined along three sections of the ternary system specified by the ratio of mole fractions xCu/xSb = 1:3, 1:1, and 3:1. Thermodynamic properties of the liquid phase were described by the Redlich–Kister–Muggianu formula. Using commercial software, phase relations in the ternary system were calculated. The results of the calculations are compared with experimental data available from literature.

The reoptimization of the binary Se-Te system

Abstract Selenium–tellurium metal films are promising materials for optical reversible memories; thus, the possibility of modeling of the phase diagram and thermodynamic properties seems to be important for industry. The Calphad method was used for a new thermodynamic assessment of the binary Se–Te system. A good agreement between calculation and experimental information is obtained.

Microstructural Characterization and Properties of Sn-Ag-Cu (SAC) Compound Induced by Zn Alloying

The microstructural properties and intermetallic (IMC) formation of Sn-Ag-Cu (SAC) through varying amounts of zinc were examined in this study while having tin held at constant composition. Samples were prepared and heated in a furnace for 168 hours to achieve complete solidification and homogenization. Results showed relatively fine microstructure primarily containing Sn dendrites, eutectic, and pro-eutectic phases. Microstructures for each alloy was similar for which majority of them formed copper-based IMCs and Sn dendrites. The alloy (0.7Sn-0.15Ag-0.1Cu-0.05Zn) containing minimal amount of zinc with high amount of Ag resulted to high Vickers hardness number. Structural analysis showed that these group of alloys composed mainly of β-Sn, Cu6Sn5, and Ag3Sn.