Indium Blog

Specifying Indium Preform Purity

  • Indium
  • Solder Preforms

  • This is the third post in my series of blog posts on pure indium preforms. This post talks about how to specify the purity level for your pure indium preforms.

    For general use, many customers order 99.99% (or 4N) indium preforms. This is a good all-around purity level, although indium is commonly available from 99.9% to 99.9999% (or 3N - 6N). Some forms of indium go beyond this, but few applications actually specify that level of purity.

    Most applications determine the purity specification on a case-by-case basis; however, one application that has unofficially “standardized” its purity level is gasketing for vacuum, hermetic, and cryogenic sealing. In this case 99.995% - 99.999% purity is recommended most often.

    Keep in mind: the higher the purity level of the indium, the more it will exhibit its unique properties. Properties like cold-welding will be enhanced at higher purity levels. If you're unsure of what purity level you need, our engineers can help you.

    This post is part of the “Complete Intro to Pure Indium Preforms” series

    Authored by previous Indium Application Manager Jim Hisert