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本文用X射线光电子能谱(XPS)和俄歇电子能谱(AES)研究了Sn-Pb合金镀层的表面氧化物膜状态并用润湿称量法测定了可焊性。结果表明,Sn-Pb合金镀层表面生成的氧化物膜主要由四价锡的氧化物(SnO_2·XH_2O和SnO_2)组成,铅的氧化物只占很少部分。这说明Sn-Pb合金镀层中锡组分较铅容易氧化。 Sn-Pb合金镀层经155℃加热16小时后,表面氧化物膜的厚度增长很大,同时可焊性明显下降。当Sn-Pb合金镀层经过热熔后,表面变得致密光亮;经155℃加热16小时后生成氧化物膜的厚度较未经热熔的在相同条件下要薄。同时可焊性也较未热熔的好。这说明Sn-Pb合金表面生成氧化物膜的厚度是影响可焊性的重要因素,热熔使Sn-Pb镀层均匀的再结晶改变了镀层结构,使之成为致密的细晶结构,增加了镀层表面的抗氧化能力。故经热熔处理的Sn-Pb合金镀层具有较长的贮存期仍能保持良好的可焊性。
The surface oxide films of Sn-Pb alloy coatings were investigated by X-ray photoelectron spectroscopy (XPS) and Auger electron spectroscopy (AES), and the solderability was determined by the wetting weighing method. The results show that the oxide film formed on the surface of Sn-Pb alloy coating mainly consists of tetravalent tin oxide (SnO 2 · XH 2 O and SnO 2), and lead oxide occupies only a small part. This shows that Sn-Pb alloy coating tin components more easily oxidized than lead. After the Sn-Pb alloy coating was heated at 155 ° C for 16 hours, the thickness of the oxide film on the surface increased greatly and the solderability decreased significantly. When Sn-Pb alloy coating after hot-melt, the surface becomes dense and bright; after heating at 155 ℃ for 16 hours the thickness of the oxide film is thinner than the same without hot-melt. At the same time solderability is better than no hot melt. This shows that the thickness of Sn-Pb alloy oxide film is an important factor affecting the solderability of hot-melt Sn-Pb coating uniform recrystallization changes the coating structure, making it a dense fine-grained structure, an increase of coating The surface of the antioxidant capacity. Therefore, hot-melt processed Sn-Pb alloy coating has a longer shelf life can still maintain good solderability.