Liquid metal droplets allow for room-temperature soldering

Nature : Conventional soldering requires heat, but as electronic devices get smaller and more sensitive, that heat can damage the materials used. Now Martin Thuo of Iowa State University in Ames and his colleagues have taken advantage of a phenomenon known as undercooling or supercooling to create tiny droplets of a metal that is normally solid at room temperature. The droplets are encased in a solid shell. To use them as solder, the researchers simply put the droplets into place and then crush them. As the metal is released, it quickly cools and solidifies. By varying details of the production, Thuo’s team was able to create particles that range in diameter from 4 nm to 5 µm and can be stored for months without breaking down. The next step is finding a metal that has a higher melting point, because many electronics generate heat that can melt the solder.