Sn-Bi-Sb系无铅钎料组织与性能研究.docVIP

 Sn-Bi-Sb 系无铅钎料组织与性能研究# 刘思栋，薛烽，周健，晏井利，唐智骄** （东南大学材料科学与工程学院，南京 211189） 5 10 15 20 25 摘要：研究了 Sn-Bi-Sb 钎料的组织、相变及润湿性。在尽量降低 Bi 含量的前提下，得到了 熔点在 170左右的钎料合金。保持 Bi 质量分数为 48%改变 Sb 的含量，可以略微缩小合金 的熔程，并提高钎料的润湿性，其中 Sb 含量为 2%时铺展率最高。扩散层分析结果表明， Sb 比 Sn 更容易与 Cu 发生扩散反应，且随 Sb 含量的提高，扩散层厚度增加，润湿时间变 长。使用含有机羧酸助焊剂，能够明显提高润湿性，得到更好的焊接效果。 关键词：材料学；Sn-Bi-Sb 钎料；显微组织；熔点；润湿性 中图分类号：TN604 Research on microstructure and properties of Sn-Bi-Sb solder alloys LIU Sidong, XUE Feng, ZHOU Jian, YAN Jingli, TANG Zhijiao (Materials Science and Engineering School, Southeast University, Nanjing 211189) Abstract: In this paper, the microstructures, phase transformations and wettability of Sn-Bi-Sb solder alloys based on Sn-Bi binary solder were investigated. By adjusting the content of Bi, several Sn-Bi-Sb alloys were found, which melting points are approximately 170℃. Keeping the content of Bi at 48%(mass fraction), the melting ranges of alloys can be slightly reduced by changing the content of Sb, and the wettability of the alloys are improved. The spreading rates of Sn-48Bi-xSb solders on copper are enhanced by addition of Sb, which achieve the highest rate at 2% Sb. The diffusion layers of the solders were analysed, and the results show that the diffusion reaction of Sb into Cu occur easier than Sn. The thickness of the diffusion layers are increased with addition of Sb. But the diffusion needs a period of time, which means a longer wetting time. Therefore, the content of Sb need be controlled in order to obtain better match between the spreading rate and the wetting time. By using industrial flux, the wettability can be improved. Key words: material science; Sn-Bi-Sb solder; microstructure; melting point; wettability 30 0 引言 Sn-Pb钎料是近几十年来电子行业广泛应用的一种连接材料，然而铅及其化合物是有毒 物质，对环境和人体健康危害极大。近年来，随着人类环保意识的增强，各国相继通过立法 禁止使用含铅的产品，电子组装业中钎料合金的无铅化已经成为了一个不可逆转的趋势。 35 40 无铅钎料主要有 Sn-Ag、Sn-Cu、Sn-Zn 和 Sn-Bi 四大体系。由于在某些特殊场合下，要 求有较低的焊接温度，而 Sn-Ag、Sn-Cu 和 Sn-Zn 系列钎料因熔点较高无法使用。Sn-Bi 二 元合金钎料共晶温度只有 138℃，能够满足低温焊接的温度要求[1]。Sn-Bi 系钎料作为 Sn-