摘 要

由于电子产品的集成度越来越高，焊点的使用条件越来越严格,因而对其可靠性提出了更高的要求。焊点合金的凝固组织及其热稳定性对焊点的抗疲劳和蠕变强度具有重要影响。目前已开发出Sn-Ag、Sn-Cu、Sn-In及Sn-Bi四个系列的无铅钎料，其中Sn-Bi系钎料因其接近Sn-Pb钎料的熔点和低廉的价格尤其受到重视，且合金基体中固溶大量的Bi，这是其他系列的合金所不具有的特征。

拟通过急冷法制备成分为43Sn-57Bi的快速凝固无铅钎料，同时与普通凝固钎料进行对比研究。对快速凝固与普通凝固钎料的组织，熔化区间，润湿性等进行对比研究，研究出快速凝固钎料在钎焊时较普通凝固钎料的优越性及实际应用的可行性，为发展新型、可在表面组装行业广泛应用的快速凝固无铅钎料提供理论基础。

主要研究结论：（1）通过分析快速凝固装置，得到快速凝固装置的影响参数有：辊面线速度、两辊间隙大小、喷嘴到辊面间距等。并且在多次运用控制变量法之后得到一个较优的工艺参数。（2）相比热压延工艺制成的Sn-Bi薄带，快速凝固制成的薄带组织更加均匀，且固液相更高，溶化温度区间更加小。（3）快速凝固工艺制备的0.17mm钎料和热压延工艺制备的0.17mm钎料冲成3.8mm×4.8mm的焊片经过润湿性实验之后，润湿面积分别为44.9mm²和39.4mm²。相比热压延工艺，快速凝固工艺制作的Sn-Bi钎料的合金的润湿性更好。

关键词：SMT；快速凝固技术；Sn-Bi共晶合金；钎料

Abstract

The requirements of solder joints has become more and more strict, Because the integration of electronic products is higher, so higher requirements is put forward for the reliability of the electronic products. The solidification microstructure and thermal stability of the solder alloy have important influence on the anti fatigue and creep strength of the solder joints. Currently has developed Sn-Ag, Sn-Cu, Sn-In and Sn-Bi four series of lead-free solder, which Sn-Bi solder due to its proximity to the melting point of Sn-Pb solder and low prices are particularly valued, and matrix alloy in solid solution in a large number of Bi. This is other series alloy has characteristics.

The rapid solidification lead-free solder of 43Sn-57Bi was prepared by rapid solidification method. Comparative study on rapid solidification and solidification solder, melting range, wettability, rapid solidification solder brazing solder than conventional solidification of superiority and practical application feasibility in, for the development of the model, on the surface assembly widely used in the industries of rapid solidification of lead-free solder and provide a theoretical basis.

Main research conclusions: (1) Through the analysis of rapid solidification device, the influence parameters of the rapid solidification device are: the roller surface line speed, the size of the two roller gap, the nozzle to the roller surface spacing, etc.. And after many times using the control variable method to debug a better process parameters. (2) Compared to the hot rolling process is made of Sn Bi thin strip, made by rapid solidification strip microstructure is more uniform, and the solid - liquid phase with higher, melting temperature range. (3) The size of 3.8mm × 4.8mm solder, rapid solidification of 0.17mm solder and hot pressed 0.17mm solder wetting area were 44.9mm² and 39.4mm². Compared with hot calendering process, Sn-Bi alloy fiber material rapid solidification process the better wettability.

Key words: SMT; Rapid solidification technology; Sn-Bi eutectic alloy; solder

目 录

摘 要 I

第1章 绪论 1

1.1 表面组装技术简介及应用 1

1.2 传统锡铅钎料 2

1.3 无铅钎料 3

1.3.1 无铅钎料的研究现状 3

1.3.2 无铅钎料的类别 4

1.4 快速凝固技术 6

1.4.1 快速凝固的方法 6

1.4.2 快速凝固技术的特点 8

1.5 研究意义与内容 9

1.5.1 研究意义 9

1.5.2 研究内容 9

第2章 实验方法 10

2.1 合金的熔炼 10

2.2 钎料薄带的制备方法 10

2.2.1 热压延制备工艺 10

2.2.2 快速凝固技术制备工艺 11

2.3 显微组织观察 12

2.4 熔化特性及凝固特性分析（DSC） 12

2.5 润湿性测试 13

第3章 实验结果与分析 14

3.1 实验装置设计及影响参数 14

3.1.1 实验装置的设计 14

3.1.2 快速凝固实验装置的影响参数 15

3.2 常见薄带成型效果不良的情况 18

3.3 Sn-Bi共晶钎料显微组织及物相分析 18

3.4 Sn-Bi钎料的DSC分析 21

3.5 Sn-Bi钎料的润湿性能测试 24

第4章 结论 26

参考文献 27

致 谢 28

第1章 绪论

1.1 表面组装技术简介及应用

现代表面组装技术 SMT(Surface Mounting Technology)是电子信息产业迅速壮大和突飞猛进的主要支柱^[1]。这种表面组装技术使得电子产品进一步微型化、薄型化、多功能化^[2]。

1）SMT技术在现代通信设备上的应用