| 化学镀和电镀镍合金与无铅焊料的反应润湿行为 | |
| Alternative Title | Reactive wetting of chemically and electrochemically deposited nickel alloys by Pb-free solders |
| 郭建军 | |
| Subtype | 博士 |
| Thesis Advisor | 冼爱平 |
| 2007-06-05 | |
| Degree Grantor | 中国科学院金属研究所 |
| Place of Conferral | 金属研究所 |
| Degree Discipline | 材料物理与化学 |
| Keyword | Ni-fe镀层 无铅焊料 Ni(p)化学镀层 润湿 界面反应 |
| Abstract | 本文结合润湿性能测量和界面分析研究了Ni合金镀层的反应润湿行为。通过化学镀的方法制得不同P含量的Ni(P)镀层，P含量在0～16.6％之间变化。润湿天平测量结果显示，镀层中的P含量对Sn-3.8Ag-0.7Cu 无铅焊料在镀层上的润湿性能影响很小。然而，对P含量高的镀层退火处理后，焊料在Ni(P)镀层的润湿力下降，润湿速率减慢。这种润湿性能的下降是由于退火过程中Ni3P粒子的析出阻碍了Ni镀层在液态焊料中的溶解所导致的。 与非反应元素P不同，Fe在Ni基体中的添加不仅改变了焊料与基体之间的金属间化合物的形态，而且还提高了基体的润湿性能。当Fe含量大于29%小于65％时，NiFe镀层比纯Ni镀层更好的的润湿性能。通过SEM和EDX分析，在纯Ni镀层和液态焊料的界面处形成Ni3Sn4金属间化合物，而Ni-Fe基体与液态焊料之间的界面化合物则为FeSn2。Ni-Fe镀层润湿性能的提高被认为是与界面反应中FeSn2的的形成驱动力更大有关。 焊料回流过程中形成的FeSn2 化合物比Ni3Sn4 要小得多，并在界面形成一紧密排列的连续层。Ni3Sn4则在FeSn2 化合物与焊料的界面处以非均匀的方式生长。 Fe含量大于65％的Ni-Fe基体的润湿性能比Fe含量更小的镀层的润湿性能要差得多，而纯Fe的润湿性能最差。XPS分析表明，高Fe含量的试样中的氧化物和氢氧化物的厚度比低Fe含量的试样要厚得多。纯Fe镀层上的氧覆盖物最厚。因此，随着Fe含量提高所导致的镀层可焊性的下降来自于试样表面更厚的氧化物和氢氧化物层。 对于SnBi共晶含量与Ni合金镀层在不同温度下(60~120℃)的固态反应，纯Ni镀层和纯Fe镀层上的化合物分别为Ni3Sn4和FeSn2，然而，Ni-Fe镀层上的界面化合物由与基体相连的一连续FeSn2层和FeSn2上分布的一些孤立的扇贝形Ni3Sn4组成。在所有的含Fe镀层中，基体与焊料的反应速率均比纯Ni镀层要慢得多。反应速率的减慢直接与不同基体上所形成的不同化合物有关。 |
| Other Abstract | Reactive wetting behavior of Ni-alloy platings was investigated by combining wetting measurements with interfacial analyses. Ni(P) platings were prepared by electroless deposition in which the P content varied up to 16.6at.%. Wetting balance measurements showed that P content in the as-deposited plating had little effect on wetting by the Sn-3.8Ag-0.7Cu lead-free solder. However, when the P-rich plating was annealed, wetting force was reduced and wetting kinetics slowed. Such degradation in wetting properties was shown to result from precipitation of Ni3P particles, which inhibited dissolution of the Ni-plating by the liquid solder. Different from the non-reactive element of P, the addition of Fe in the Ni-based substrate not only changed the type of IMCs between substrate and solder but also enhanced the wetting property of the substrate. When Fe content was greater than 29% but less than 65%, NiFe platings had better wetting property than pure nickel plating. By SEM and EDX analysis, Ni3Sn4 formed at the interface between liquid solder and pure Ni plating, while FeSn2 formed at the interface between liquid solder and NiFe substrate. The improved wetting on Ni-Fe platings is believed to be related to the greater driving force for interfacial reaction associated with FeSn2 formation. The FeSn2 compound formed during solder reflow was much finer than Ni3Sn4 and grew into a densely packed thin continuous layer at the interface. The coarse Ni3Sn4 grew non-uniformly at the interface at a faster rate than the growth rate of FeSn2. The wetting property of the NiFe platings with Fe content more than 65% was much worse than that of platings with less Fe content with the wetting property of pure Fe platings being the worst. XPS analysis indicated that the oxide and hydroxide layers in the samples with higher Fe contents were much thicker than those with lower Fe contents. The oxide coverage on the pure Fe plating was thickest. Thus, the decline of solderability of platings with higher Fe contents resulted from the thicker oxidation and hydroxid layer on the surface. For the solid reaction of eutectic SnBi solder with various Ni-alloy platings during aging at different temperatures (60~120℃), the IMC formed on pure Ni and pure Fe platings was Ni3Sn4 and FeSn2 , respectively, while on NiFe plating the interfacial IMC was a layer of FeSn2 adjacent to the substrate and some separated scallop-shaped Ni3Sn4 above the FeSn2 layer. In all Fe-containing platings, the reaction rates of the substrates with the solder were much lower than that of pure Ni plating. The reduced reaction rate was directly related to the different IMCs formed on different substrates. |
| Pages | 128 |
| Language | 中文 |
| Document Type | 学位论文 |
| Identifier | http://ir.imr.ac.cn/handle/321006/16845 |
| Collection | 中国科学院金属研究所 |
| Recommended Citation GB/T 7714 | 郭建军. 化学镀和电镀镍合金与无铅焊料的反应润湿行为[D]. 金属研究所. 中国科学院金属研究所,2007. |
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