Thermochemistry and Phase Equilibria in Ag-Cu-Ni-Sn

The aim of this project is the experimental investigation and thermodynamic assessment of the quaternary system Ag-Cu-Ni-Sn including the binary and ternary sub-systems. This basic research work on intermetallic systems will also contribute to the COST-531 action. This COST action was succesfully initiated in order to generate and systematize information on thermochemistry, phase relations and physical properties of intermetallic systems relevant to lead-free solder materials. A lead-free solder database will be created which forms the basis for a systematic alloy design which is desired to avoid complex and time consuming trial and error methods. Lead and lead containing chemicals are among the top chemicals posing a considerable threat to human life and environment. Examples for new lead-free solders are Ag-Sn, Cu-Sn and Ag-Cu-Sn alloys with Sn as the main component (> 90 mass%). Other alloying components in discussion are Bi, In, Sb and Zn. The metals Ag, Cu, Au, Ni and Pd are commonly used as contact materials for solder joints. Thus binary, ternary and higher order intermetallic systems of the elements mentioned above are relevant for lead-free solders. Most of the binary systems are rather well investigated whereas uncomplete literature data are available for the ternary and higher order systems. For this project the investigation of interactions of the intermetallic solder system Ag-Cu-Sn with nickel as the contact material is planned. This includes measurements of thermochemical data in the solid as well as in the liquid state using calorimetry and e.m.f.-methods and the evaluation of phase relations by thermal analysis, XRD and metallography (EPMA). Furthermore diffusion experiments with Ag(Cu)-Sn alloys and Ni will be done. Thermodynamic calculations and assessments of the quaternary system Ag-Cu-Ni-Sn and its ternary sub-systems will provide all relevant phase diagram information in aggreement with experimental results. This work is also planned to gain deeper insight in relationships of phase equilibria, thermochemical properties and diffusion behaviour. Furthermore theoretical aspects of diffusion (Kirkendall effect) and enthalpy of mixing in the liquid state (pseudo-potential calculations and Fermi enthalpy) will be investigated.

The aim of this project is the experimental investigation and thermodynamic assessment of the quaternary system Ag-Cu-Ni-Sn including the binary and ternary sub-systems. This basic research work on intermetallic systems will also contribute to the COST-531 action. This COST action was succesfully initiated in order to generate and systematize information on thermochemistry, phase relations and physical properties of intermetallic systems relevant to lead-free solder materials. A lead-free solder database will be created which forms the basis for a systematic alloy design which is desired to avoid complex and time consuming trial and error methods. Lead and lead containing chemicals are among the top chemicals posing a considerable threat to human life and environment. Examples for new lead-free solders are Ag-Sn, Cu-Sn and Ag-Cu-Sn alloys with Sn as the main component (> 90 mass%). Other alloying components in discussion are Bi, In, Sb and Zn. The metals Ag, Cu, Au, Ni and Pd are commonly used as contact materials for solder joints. Thus binary, ternary and higher order intermetallic systems of the elements mentioned above are relevant for lead-free solders. Most of the binary systems are rather well investigated whereas uncomplete literature data are available for the ternary and higher order systems. For this project the investigation of interactions of the intermetallic solder system Ag-Cu-Sn with nickel as the contact material is planned. This includes measurements of thermochemical data in the solid as well as in the liquid state using calorimetry and e.m.f.-methods and the evaluation of phase relations by thermal analysis, XRD and metallography (EPMA). Furthermore diffusion experiments with Ag(Cu)-Sn alloys and Ni will be done. Thermodynamic calculations and assessments of the quaternary system Ag-Cu-Ni-Sn and its ternary sub-systems will provide all relevant phase diagram information in aggreement with experimental results. This work is also planned to gain deeper insight in relationships of phase equilibria, thermochemical properties and diffusion behaviour. Furthermore theoretical aspects of diffusion (Kirkendall effect) and enthalpy of mixing in the liquid state (pseudo-potential calculations and Fermi enthalpy) will be investigated.