Indium Blog

NanoFoil® Coating

  • Solder Alloys
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  • InCuSil is a common term for an alloy of indium, copper, and silver which (depending on composition) has various melting points in the brazing range. We at the Indium Corporation use InCuSil as an outer coating on standard NanoFoil®, to help the Ni/Al bond with the surrounding solder layers. (Seen here: a thin layer of InCuSil [right] partially stripped from reacted NanoFoil® [left].)

    When alloyed at 61.5%Ag, 24%Cu, and 14.5%In, the resulting metal has a solidus point of 630°C and a liquidus of 705°C. It is applied to the NanoFoil® as a final PVD (Physical Vapor Deposition) coating step, to a thickness of 1 micron (μ) per side.

    Since the only function of the InCuSil alloy on NanoFoil® is to promote bonding, there are some applications where it is not needed – and therefore not applied. These applications are generally for fuses and other pyrotechnic devices.

    If you’d like to learn more about NanoFoil®, send us a question!

    Authored by previous Indium Application Manager Jim Hisert