Morphology and intermetallics study of (Sn-8Zn-3Bi)-1Ag solder under liquid-state aging

• Published in: Advanced Materials Research
• Main Author: Jasli N.A.; Hamid H.A.; Mayappan R.
• Format: Conference paper
• Language: English
• Published: 2013
• Online Access: https://www.scopus.com/inward/record.uri?eid=2-s2.0-84871903571&doi=10.4028%2fwww.scientific.net%2fAMR.620.273&partnerID=40&md5=a6fd2df1e1ae092aa13e15abf55400bf

This study investigated the effect of Ag addition on the morphology and growth rate of Cu5Zn8, Cu6Sn5 and Cu3Sn intermetallics in the Sn-8Zn-3Bi solder. The solder was prepared by mixing 1wt% of Ag into 99wt% of Sn-8Zn-3Bi solder. The intermetallics were formed by liquidstate aging, whereby the solders were reacted on Cu substrate above the melting temperature of the solder. The reflow was done at 250°C and 270°C at various soldering times. A scanning electron microscope (SEM) was used to observe the morphology of the intermetallic phase and energy dispersive X-ray (EDX) was used to identify the elemental composition. The Sn-8Zn-3Bi solder reacting with Cu substrate formed a single Cu5Zn8 intermetallic layer with a flat structure. On the other hand, the reaction between (Sn-8Zn-3Bi)-1Ag solder and Cu substrate produces Cu6Sn5 intermetallic. This Cu6Sn5 intermetallic has a scallop structure. As the soldering time increases, a second layer, identified as Cu3Sn starts to grow. The thickness of the intermetallics increases with aging temperatures and time. The addition of Ag into the Sn-8Zn-3Bi solder has significantly suppressed the formation of Cu5Zn8 intermetallic and promoted the growth of Cu6Sn5 intermetallic. © (2013) Trans Tech Publications, Switzerland.