Matte-finish Solder Joints after Lead-free Wave Soldering

摘要

Most joints soldered using lead-free alloys exhibit a dull or frosty appearance, which differs from the smooth, bright, shiny surfaces of tin/lead solders. This article looks at several reasons for this phenomenon. Most joints soldered with lead-free solders exhibit a dull or frosty appearance. This differs from the smooth, bright, shiny surfaces experienced with tin/lead solders. This is typical of SAC alloys (tin/silver/copper) commonly used in lead-free soldering applications. There are a number of reasons for this occurrence. One reason is that these lead-free alloys contain three different elements, and thus three eutec-tics, during solder solidification. These eutectics each have their own melting point and solidification behavior.