Indium Blog

Properties and Uses of Low-Temperature Solder Alloys – (Part 4)

  • Bismuth
  • Indium
  • Indium Alloy

  • If you missed the first part of this series, you can find it here.

    We have defined low-temperature alloys and discussed two interesting properties of these alloys: melting points and expansion during cooling. We are still really just scratching the surface. Let’s discuss some of the other potential uses for low-temperature alloys.

    One popular use of low-temperature alloys is in step soldering. Step soldering is the term given to the use of solders with different melting points to sequentially solder assemblies and sub-assemblies without re-melting the previous solder joints. Low-temperature alloys can be used as a last soldering step, even after SnPb solder bonds have been made. Just make sure your reflow temperature is still low enough to not melt the other alloys!

    Another handy use for low-temperature solder alloys is the interconnection of molded components. Certain plastics that are used in these devices may melt using traditional solders, but our Engineers can help you find an alloy with a melting point below that of the plastic in question.

    We should also mention that low-temperature alloys can be used as a replacement for mercury in some applications. Liquid solder alloys are much safer to work with!

    One more potential use I cannot forget to mention is the thermal and electrical conductivity of low temperature alloys – both for bonding and liquid metal heat transfer. Many of these alloys, especially those containing indium, have very good thermal conductivity relative to most solders. Liquid alloys can also be used as a heat exchange medium. Interesting, right?

    If you’re curious about any of these applications (or one of the many other applications I didn’t mention), send me an email:


    Authored by previous Indium Application Manager Jim Hisert