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What type of tin plating should I use for my application?

Tin plating is provided in two general types of deposits, bright and matte. Both can be obtained from an alkaline or acidic bath. The acidic chemistries are most common today. The advantages of each type are as follows:

Bright Tin

  • aesthetic appeal
  • lubricity
  • corrosion protection
  • electrical enhancement to substrate

Matte Tin

  • solderable
  • electrical enhancement to substrate
  • non-reflective

For applications where cosmetics, lubricity or the appearance of the deposit are critical, bright tin is generally preferred.  However the additional of organic brighteners in the deposit can impede solderability or epoxy bonding.  For applications where joining is a key design requirements, a matte tin deposit should be selected.  Since the solder bond occurs with the substrate and not the actual tin coating, an underplate of a pure nickel underplate such as sulfamate or unbrightened watts deposit serves as an excellent base to a solderable tin deposit for the best possible solderable finish.