中國有色金屬學報(英文版)
Transactions of Nonferrous Metals Society of China
| Vol. 15 No. 6 December 2005 |
LIU lin(劉 琳)1, HU Yong-fang(胡永芳)1, YAO Li-hua(姚立華)1
（1. College of Materials Science and Technology,
Nanjing University of Aeronautics and Astronautics, Nanjing 210016, China;
2. 14th Research Institute, China Eletronics Technology Group Corporation,
Nanjing 210013, China）
Abstract: Several important properties of the micron-powdered Sn-Ag-Cu-Ce solder, including the spreadability, spreading ratio, wetting time, and melting point, were investigated for verifying the effects of rare earth element Ce on solderabilities of micron-powdered Sn-Ag-Cu solder. The solidus and the liquidus of the micron-powdered Sn-Ag-Cu-Ce solder are 193.6℃ and 218.4℃, respectively, about 28℃ and 3℃ lower than the melting point of the block Sn-Ag-Cu solder, which reminds the existence of the surface effect of the micron-powdered solder. By adding Ce into Sn-Ag-Cu alloy, its wetting time on pure copper can be obviously decreased. For the Sn-Ag-Cu-0.03%Ce, the soldering temperature is 250℃, and the wetting time on pure copper is close to 1s, with the soldering temperature approaching to 260℃, the wetting time is dropped to 0.8s, which is close to the wetting time, 0.68s, of Sn-Pb solder at 235℃.
Key words: lead-free solder; Sn-Ag-Cu-Ce alloy; wetting time; solidus; liquidus
