Yale develops greener solder

Until recently, virtually all solder was made from a tin-lead alloy. But because lead is a toxic substance, there is a lot of interest in trying to find a greener alternative. Recent legislation in Japan and the European Union bans the import of electronics with lead solders. But until now, scientists had difficulty coming up with a suitable alternative for lead-based solders that are just as strong and have a similarly low melting point.

Now Ainissa Ramirez, associate professor at the Yale School of Engineering and Applied Science, and her team have developed a non-toxic solder made of tin silver and containing iron particles. Not only is using a tin-silver alloy an environmental advantage, the addition of iron particles has other benefits.

First, the iron makes the alloy much stronger than it would ordinarily be. When an external magnetic field is applied to the molten solder, these particles align themselves within the solder, making it even stronger once it re-solidifies.