THE MICROSTRUCTURES OF THE SN-ZN-AL SOLDER ALLOYS

The microstructures of the Sn-Zn-Al lead-free solders have been invest igated using scanning electron microscopy. The Al and Zn contents of t he solders investigated were 0.45%similar to 4.5% and 8.55%similar to 85.5%, respectively. The solders were prepared from the Zn-5Al master alloy and Sn. The precipitates formed in these solders were analyzed f or their compositions with energy dispersive spectroscopy. The eutecti c temperature and the transition temperatures of these solders upon co oling were identified with cooling curves as well as with differential scanning calorimetry.