Test of wettability of lead-free solders

This paper deals with wettability of widely used lead-free solders. Tested solders were lead-free solders Sn-3,8Ag-0,7Cu, Sn-4Ag, Sn-1Cu and Pb containing solder Sn-37Pb. Wetting balance method was used for testing wettability of the solders mentioned above according to standard ČSN EN 60068-2-54. Temperature of melted solder was 235 °C for Sn-37Pb and 248 °C for lead-free solders. Wetting was tested for copper and nickel in form of wire with diameter 1 mm and length 20 mm. Samples were dipped into melted solder and total force actuating in time during the test was measured. Key parameters for characterization wetting behavior of solder were maximum wetting force and the time to reach 2/3 of that force. The influence of nitrogen atmosphere was tested as well.