(大連理工大學(xué) 材料工程系， 大連 116024)
摘 要: 研究了(Sn-9Zn)-xCu無鉛釬料的微觀組織、潤濕性能和力學(xué)性能。 Cu的加入使得Sn-9Zn釬料中針狀富Zn相逐漸轉(zhuǎn)變?yōu)镃u-Zn化合物， 當(dāng)Cu含量為8%時， Cu6Sn5相生成。 Sn-Zn-Cu合金熔點隨著Cu含量增加而升高， 同時潤濕性隨Cu的加入得到顯著改善。 使用中性活性松香釬劑，釬料與Cu箔釬焊時的潤濕角顯著減小。 Sn-9Zn的潤濕角為120°， 而(Sn-9Zn)-10Cu的潤濕角為54°。 這是由于Cu的加入降低了Zn的活性， 減少了Zn在釬料表面氧化， 降低了液態(tài)釬料表面張力， 使得釬料能獲得較好的潤濕性。合金在2%Cu時獲得較高的強度， 隨著Cu含量的增加， Cu-Zn化合物相對增多， 抗拉強度有所下降；而合金的塑性隨著Cu的加入迅速下降。
關(guān)鍵字: 無鉛釬料；Sn-Zn-Cu；微觀組織；潤濕性；抗拉強度
（ Department of Materials Engineering， Dalian University of Technology， Dalian 116024， China）
Abstract: The microstructures， wettability and mechanical properties of (Sn-9Zn)-xCu lead free solders were investigated. The addition of Cu element leads the needle Zn rich phase to transform into Cu-Zn compounds and when Cu is 8%， Cu6Sn5 phase emerges. The melting point increases with increasing Cu content; while the wetting properties is improved dramatically. When the solder reflows on Cu substrate， the wetting angle decreases greatly using mildly active rosin (RMA) flux. The wetting angle of Sn-9Zn is 120°; while that of (Sn-9Zn)-10Cu is 54°. The improvement on wettability is due to the addition of Cu which decreases the activity of Zn and refrains the oxidation of Zn atoms at the surface of liquid solder. Better wetting behavior is gotten because of the lower surface tension of liquid solder. And the solders get the higher tensile strength when Cu content is 2%. With more Cu addition， more Cu-Zn compounds formation deteriorates the solder strength and the ductility decreases greatly with Cu addition.
Key words: lead free solder; Sn-Zn-Cu; microstructure; wettability; tensile strength
