CuSnTi钎料焊膏与焊片钎焊性能对比

为验证CuSnTi_8-5焊膏的熔化条件可以使用与焊片相同的焊接工艺,以及其钎焊接头性能不低于焊片接头性能,分别使用差热分析(DSC)、铺展性试验及测试接头力学性能,并使用扫描电子显微镜(SEM)与能谱仪(EDS)对接头进行组织分析,研究比较了焊膏与焊片相关性能表现。试验结果表明,CuSnTi_8-5焊膏与焊片有着接近的固液相温度,其完全满足焊片的焊接工艺;焊膏的润湿铺展性能优于焊片,且其钎焊接头强度高于焊片接头。分析其原因,在于同样的钎焊温度下,焊膏与基材作用时间长,可获得更多的润湿动能,因此呈现更高的铺展系数。另外,焊片无法像焊膏在焊缝周围形成明显的润湿圆角,影响了接头力学性能。通过组织分析,二者钎缝与母材间形成的Cu-Ti固溶体状态不同是造成了润湿性与接头力学性能差异的原因。

Brazing performance comparison between CuSnTi alloy solder paste and solder foil

To verify the melting condition of CuSnTi_8-5 solder paste,the same welding process of the solder foil could be used,and properties of soldered joints with solder paste were not lower than that of soldered joint with solder foil.Differential thermal analysis(DSC),wettability test and mechanical properties of the joint were tested.The microstructure of the joint was analyzed by scanning electron microscope(SEM)and energy dispersive spectrometer(EDS).The related properties of solder paste and solder foil were compared.The results showed that CuSnTi_8-5 solder paste had a close solid-liquid temperature to the solder foil,which fully met the welding process of the solder foil.The wettability and spreadability of the solder paste was better than that of the solder foil,and the strength of the soldered joint with the solder paste was higher than that of the soldered joint with the solder foil.The reason was that under the same soldering temperature,the solder paste had a longer interaction time with the substrate,which obtained more wetting kinetic energy,so it presented a higher spreading coefficient.In addition,the solder foil could not form obvious wetting fillet around the weld as the solder paste did,which affected mechanical properties of the soldered joint.Through analysis of microstructure,the difference in wettability and mechanical properties of the soldered joints was due to the different state of Cu-Ti solid solution formed between soldering seams with the solder paste and the solder foil and the base metal.