Properties of SnZn lead free solders bearing rare earth Y

Abstract

Rare earth (RE) Y has been incorporated into eutectic SnZn solders to study the wettability, mechanical properties, oxidation resistance, microstructures and thermal fatigue behaviours. The results indicate that adding trace amount of RE Y can remarkably improve the wettability of SnZn solders. When the content of RE Y is 0?06 wt-%, the tensile and shear forces of SnZn-xY solder joints give 24?1% and 27?2% increase after soldering. In addition, it is found that SnZn0?06Y has better oxidation resistance than that of SnZn solder, and the microstructures of SnZn solders can be refined by the addition of RE Y; the size of Zn rich phase can be reduced obviously. Moreover, SnZn0?06Y shows superior thermal fatigue property over SnZn solders. It can be concluded that the optimum content of RE Y is 0?06 wt-% for SnZn solders.

Development of lead-free solders in China during the past decade

“…稀土元素 Er [24] 和 Y [25] 对于 Sn3.8Ag0.7Cu 钎料也具有明显的改善作用, Er 的添加范围控制在 0.05%~0.25%, 稀土可以最大 限度的发挥改善性能和细化金属间化合物的作用, 而稀土 Y 的最佳添加范围是 0.1%~0.25%. 稀土元素 Er [26] 和 Y [27] 对 Sn9Zn 钎料也具有类似的改性作用, 同时对抗氧化性也有一定的帮助, 皋 利 利 [28] 针 对 含 稀 土 元 素 Pr, Nd 的 Sn3.8-Ag0.7Cu 钎料和焊点进行研究, 证明了适量添加稀土 元素可以降低液态钎料表面张力, 改善钎料的润湿 性, 另外拉伸-剪切和抗蠕变特性也得到显著的提高.…”

Effects of Yttrium Addition on the Microstructure Evolution and Electrochemical Corrosion of SN-9Zn Lead-Free Solders Alloy

“…The rare earth (RE) elements have been considered as vitamins of metals, because a tiny amount of RE elements can significantly improve the properties of alloys. Zhang et al [ 27 ] reported that the proper amount of Y can not only refine the structure of the Sn-Zn alloy but also improve the wettability and mechanical properties of the Sn-Zn/Cu solder joint and enhance the oxidation resistance of the solder alloy. Besides, as connecting material, the corrosion resistance of the solder plays a decisive role in the service life and safety of electronic products.…”