Effects of Different Fluxes on the Spreadability of Zn-20Sn Solders

The spreadability of Zn-20Sn solders on Cu substrate was researched by using self-made flux, silver brazing 102 and medium activity rosin (RMA), and the characteristics of intermetallic compounds the appearance of solder joints were compared and analyzed at soldering joints. Results indicated that Zn-20Sn solders exhibited excellent spreadability by using self-made flux. A shoot IMC layer was closed to the solder while a flat IMC layer was presenting adjacent to the Cu substrate and the middle layer. Moreover, the characteristics of IMC and the appearances of soldered joints varied by using different fluxes.