Tin plating is applied to enhance appearance and/or to provide corrosion resistance. Provide corrosion resistance of copper plus bars in corrosive environment. Tin can be plated in a bright or matte (dull finish)
Bright tin is ductile and offer a combination of good corrosion resistance and excellent cosmetic. Bright tin is not considered to be solderable.
Matte tin is highle solderable and also offers good corrosion resistance and ductility, but is not as cosmetically pleasing. Parts that are tin plated should be soldered within a few weeks after plating unless steps are taken to prevent oxidation of the tin plating. Copper base metals should have a sulfamated nickel diffussion barrier to prevent the formation of a copper-tin inter-metallic that will affect the solderability of the object.