三种高Sn无铅钎料的表面张力和润湿性能研究

Study of surface tension and wettability for three kinds of high Sn-containing lead-free solders

采用悬滴法测量了3种无铅钎料合金(Sn-3.0Ag-0.5Cu、Sn-0.7Cu与Sn-9.0Zn)在260℃时的表面张力,分别为525.5,534.8和595.4 mN/m;同时采用座滴法测量了其在260℃熔融状态下与Cu基板的接触角,分别为24.5°、28.0°和102.5°,并且与传统Sn-37.0Pb钎料进行了比较研究。结果表明,无铅钎料合金的表面张力与接触角均大于Sn-37.0Pb钎料。结合Young-Dupre公式讨论了钎料合金表面张力与其润湿性能的相关性,认为Sn基钎料合金在Cu基板上的润湿性能主要取决于其表面张力。

The surface tensions of three lead-free solders alloys,i.e.Sn-3.0Ag-0.5Cu,Sn-0.7Cu and Sn-9.0Zn,were tested with pendent drop method at 260 ℃,average surface tension values of the above solders alloys were 525.5,534.8 and 595.4 mN/m,respectively.Contact angles of three solders alloys on Cu substrate with rosin flux are also measured with sessile drop method,the average values were 24.5°,28.0° and 102.5°,respectively.And they were compared with traditional Sn-37.0Pb eutectic solder alloy.The results show that the both surface tensions and contact angles of lead-free solders alloys are bigger than Sn-37.0Pb alloys.According to the Young-Dupre equation,the relationship between the surface tension and the wettability of the solders alloy is discussed,the wettability of solders alloys mainly depends on the surface tension.