稀土Ce加速Sn晶须生长的研究

Study of Rapid Growth of Tin Whisker Accelerated by Rare Earth Ce

摘要:

稀土被认为是金属中的“维他命”，在钎料中添加微量的稀土Ce可以显著地改善钎料合金的综合性能。然而，当钎料中添加过量的稀土时，将会发现Sn晶须的快速生长现象。结果表明，如果将Sn3.8Ag0.7Cu1.0Ce钎料内部的稀土相暴露于空气中，稀土相将发生氧化而产生体积膨胀，钎料基体对体积膨胀的抑制作用将使稀土相内部产生巨大的压应力从而加速Sn晶须的生长

Abstract:

Rare earth elements are recognized as the “vitamin” of metals, and trace amount of rare earth Ce can effectively improve the comprehensive properties of the solder alloy. However, rapid tin whisker growth has been found when excessive amount of rare earth were doped in the solder alloys. The results indicated that the rare earth-phase will be oxidized and induce volume expansion when Sn 3.8Ag0.7Cu1.0Ce solder was exposed in air, and the constraint action of the solder matrix on the volume expansion of the oxidized rare earth-phase will result in a compressive stress that will accelerate the growth of tin whiskers