(1. 湖南大學 材料科學與工程學院，長沙 410082；
2. 國防科技大學 計算機學院，長沙 410073)
摘 要: 通過對自行研制的Sn-Bi-X(X=Ag，Cu，Ge，Ce，Sb)無鉛焊料進行快速冷卻及擴散退火處理，研究其顯微觀組織和性能的變化。結(jié)果表明，冷卻速度越大，熔點越低，共晶比例越小。當甩帶速度為1 000 r/min時，熔點由190.5 ℃降低至186.2 ℃，且Sn-58Bi共晶相完全消失。擴散退火能消除Bi的粗化晶體，使組織均勻，增強焊料的力學性能，并且退火后組織穩(wěn)定。擴散退火可以作為表面貼裝生產(chǎn)工藝流程的一個工序，退火工藝以125℃保溫16 h為宜。
關(guān)鍵字: Sn-Bi系無鉛焊料；偏析；快速冷卻；擴散退火
（1. School of Materials Science and Engineering, Hunan University, Changsha 410082, China;
2. School of Computer, National University of Defense Technology,Changsha 410073, China）
Abstract:A self-fabricated Sn-Bi-X(X=Ag, Cu, Ge, Ce, Sb) lead-free solder was treated by rapid cooling and diffusion annealing, the changes of its microstructures and properties were investigated. The results show that, the faster the cooling rate, the lower the melting point and the smaller the percent of eutectic is. When the melt spinning rate is up to 1 000 r/min, the melting point decreases from 190.5 ℃ to 186.2 ℃, and the eutectic phase of Sn-58Bi disappears fully. Diffusion annealing can remove the coarse crystal of Bi, uniform the microstructure and enhance the mechanical property of Sn-Bi lead-free solder. The microstructure is stable after annealing. Diffusion annealing can be a procedure of surface mounting production process. Annealing at 125 ℃ for 16 h was approved well.
Key words: Sn-Bi lead-free solders; segregation; rapid cooling; diffusion anneal
