Tin has good conductivity and corrosion resistance while enhancing the solderability of substrates not easily soldered to. Pure tin can be obtained in both Bright and Matte finishes. Bright Tin has a high lustre and is generally preferred for electrical contact applications such as bus bars, terminals and switch components not soldered to. When soldering to Bright Tin, dewetting can occur due to organic additives used to brighten the deposit. For solderable applications, Matte Tin is preferred as it’s free of organics found in Bright Tin.
Tin deposits will oxidize over time so storage of the plated components should be considered for extending shelf life. Preplates of other metals, most commonly nickel, are also used as an effective barrier against diffusion and can significantly extend the solderability shelf life of tin plated parts.
Standards for Tin are Mil-T-10727, ASTM B545, and AMS 2408.