Research On Properties Of Sn-Ag-Cu Solder Alloy Doped With Sb

At present, the main direction of the development of the lead-free solder is diversified, wherein the Sn-Ag-Cu solder which is made by doping Cu into Sn-Ag is considered to be the most prospective replacement of Sn-Pb solder. Sn-Ag-Cu lead-free solder has good thermal fatigue properties, such as joint high intensity, narrow width of the melting temperature, good creep characteristics. Their mechanical properties and reliability are better than Sn-Pb solder. But there are still some defects in Sn-Ag-Cu solder, such as its melting temperature is higher than that of Sn-Pb solder, and its wetting property is not as good as that of Sn-Pb solder. So the Sn-Ag-Cu solder need to be improved. At present, a method of doping some kind of element into Sn-Ag-Cu solder is proposed to improve its property. For example, the performances of Sn-Ag-Cu lead-free solder doped with Bi and Ce have been researched.Sn-3.0Ag-0.5Cu solder was doped with Sb in this paper. And the melting temperature, conductibility, wetting property and microscopic structure of the solder were reported.This paper researched the effect of Sn-3.0Ag-0.5Cu doped with different ratio of Sb and the ratio is 0.1%～1.0%. One experimental data was saved every 0.1% ratio.the properties of the samples was measured by DSC and the results indicated that the melting temperature of Sn-3.0Ag-0.5Cu doped with Sb was not reduced and the melting temperature would rise if the doping ratio was too high. The conductibility of Sn-3.0Ag-0.5Cu doped with Sb was obviously improved by digital four- probe test system. Wetting angle was obtained by AUTOCAD using the method of testing its spreading area and the results showed that the wetting property was improved dramatically after doped with Sb. The microscopic structure of Sn-3.0Ag-0.5Cu doped with Sb was obtained by SEM. And the results indicated that the microscopic structure was more fine and more even. The test results showed that the properties of lead-free solder was improved. When the doping ratio of Sb was 0.5%, The property of Sn-3.0Ag-0.5Cu was improved most obviously. The melting point of Sn-3.0Ag-0.5Cu doped with 0.5% Sb was 219.621℃. the resistivity decreased by10.53% and the wetting angle decreased by 8°. The property of Sn-3.0Ag-0.5Cu was improved by the largest extent. The test results can provide the datas for this kind of lead-free solder in the actual production .