Abstract Scope |
Sn-based alloys, such as Sn-Ag-Cu, Sn-Ag-Bi, Sn-Ag-In, Sn-Cu-In, Sn-Ag-Bi-Cu and Sn-Ag-Cu-In are all important solder alloys. Although these alloys are of industrial application interests and have attracted relatively intensive investigations, it is surprising to find out that significant deviations exist regarding the liquidus temperatures obtained from Calphad-type calculation using available data bases and those determined experimentally using DSC (differential scanning calorimetry). For example, the liquidus temperature of Sn-7.0wt.%Ag-1.0wt.%Cu alloy determined by using DSC is 284.2℃, while those calculated using different data bases are 271.9, 276.2 and 287.5℃. Similar inconsistencies are observed in other Sn-based alloys. Better agreement between experimental determined and calculated results is observed regarding the invariant reaction temperatures. Sn-Ag-Cu, Sn-Ag-Bi, Sn-Ag-In, Sn-Cu-In, Sn-Ag-Bi-Cu and Sn-Ag-Cu-In alloys are prepared in this study. Their phase transformation temperatures are determined using DSC and Calphad calculation, focusing on the liquidus temperatures and the completely solidified temperatures, i.e. eutectic and solidus temperatures. |