Investigation on viscosity, surface tension and non-reactive wettability of melting Ag-Cu-Xwt%Ti active filler metals

Abstract

The microstructure, viscosity and surface tension of melting Ag-Cu-Xwt%Ti active filler metals were researched, the influence mechanism of microstructure on the viscosity and surface tension was discussed, the non-reactive wetting behavior of melting Ag-Cu-Xwt%Ti filler metals on W substrate was investigated. The research results indicate that, the microstructure of Ag-Cu filler metal is composed by Ag86Cu14 phase and Ag56Cu44 phase, while after Ti element be added in the Ag-Cu-Xwt%Ti filler metal, Cu-Ti intermetallic compounds will be formed. The different microstructures of the Ag-Cu-Xwt%Ti filler metals, especially the difference between the amounts and kinds of the intermetallic compounds, lead to the various viscosity and surface tension. Viscosity of the Ag-Cu-Xwt%Ti filler metal can be divided into low temperature zone and high temperature zone. At the low temperature zone, the viscosity increases obviously with the increasing Ti content, while at the high temperature zone, the viscosity for the four melting Ag-Cu-Xwt%Ti filler metals show little difference. With increase of the temperature, surface tension for the four melting Ag-Cu-Xwt%Ti filler metals all decrease firstly and then increase, and the temperature for the lowest surface tension is 975 °C. Moreover, with increase of the Ti content, surface tension of the melting Ag-Cu-Xwt%Ti filler metal increases gradually at both low temperature zone and high temperature zone, but the difference among them at low temperature zone is larger than that at high temperature zone. The non-reactive wetting experimental result confirms this conclusion very well.