无铅焊料sn-zn合金系焊接界面微观组织演化（本科毕业论文设计）.doc

摘 要

本文通过采用Sn-8.0Zn-xBi合金在Cu基板上回流焊的方法，研究了Bi对Sn-Zn系合金在Cu基板上焊接界面的影响。利用扫描电子显微镜和能谱仪观察和分析Bi对Sn-Zn系合金以及在Cu基板上焊接界面金属间化合物种类，形貌，厚度及生长情况的影响。结果表明：Sn-9Zn焊料是由灰色基体β-Sn相和黑色针状富Zn相所组成的二元共晶组织。Sn-9Zn-1Bi焊料和Sn-8Zn-3Bi焊料由三相组成：灰色的β-Sn相，黑色针状的富Zn相和白色片状的Bi固溶体相。
Sn-9Zn焊料合金焊接后焊接界面处形成的金属间化合物呈半球状伸入到焊料内。从焊料处往Cu板方向，金属间化合物的成分依次是Cu-Zn化合物相、Cu6Sn5相。Sn-8Zn-1Bi焊料和Sn-8Zn-3Bi焊料焊后，从焊料处往Cu板方向，金属间化合物的成分依次是Cu6Sn5相、Cu-Zn化合物相。


关键词：无铅焊料，Sn-Zn焊料，界面反应，金属间化合物


ABSTRACT

In this paper, the influence of minor Bi addition on the interfacial reaction between Sn-Zn solders and a Cu layer was studied. Scanning electron microscopy was used to observe the microstructure of IMCs formed between solders and the Cu layer. Phase distribution was determined by energy dispersive spectroscopy. The test results show that: the microstructure of the Sn-9Zn solder was composed of a grey β-Sn phase and a needle-like Zn-rich phase. While the Sn-8Zn-1Bi solder and Sn-8Zn-3Bi solder are constituted by three-phase: the grey β-Sn phase, the needle-like Zn-rich phases and a white Bi-rich phase.
After reflow, the intermetallic compounds formed at the interface between Sn-9Zn solder alloy and Cu substrate was hemisphere-like and grew toward solder matrix. The intermetallic compounds formed between Sn-9Zn solder and the Cu substrate was composed of Cu-Zn phase (close to the solder matrix) and Cu6Sn5 phase (close to the Cu layer). Whereas, after the addition of 1%Bi and 3%Bi into the solders, the interfacial reaction intermetallic compounds was composed of Cu6Sn5 phase (close to the solder matrix) and Cu-Zn phase (close to the Cu layer).


Key words：Lead-free solder, Sn-Zn solder, interfacial reaction, Intermetallic compound







目 录

中文摘要 I
ABSTRACT II
1 绪论 1
1.1引言 1
1.2国内外电子封装无铅钎料的研究现状 1
1.3无铅钎料合金的研究成果 4
1.4课题研究的意义 8
2 实验 10
2.1 实验材料及过程 10
2.2 试样的制备 10
2.3 实验设备 11
2.3.1扫描电子显微镜 11
2.3.2能谱仪 13
3 实验数据以及结果分析 15
3.1 焊料合金的显微组织分析 15
3.2 焊后界面能谱分析 16
3.3实验结果分析 19
3.3.1钎焊过程中金属间化合物的生长过程 19
3.3.2 Cu-Zn 金属间化合物生长的驱动力 21
3.3.3 钎焊过程中Cu-Zn金属间化合物的溶解过程 21
4 结论 24
参考文献 25