102 West Woodland Street
Watertown, TN 37184
Surface Finishing Since 1978
Properties of Tin
Tin is a soft, ductile, silvery-white metal that is not easily oxidized in air. It is generally considered non-toxic making it useful for food contact surfaces. For electrical applications, tin is specified as a coating for copper to prevent the characteristic greenish blue oxide from forming in corrosive environments. Tin is not as conductive as copper but, can offer a good compromise to protecting copper as a means of maintaining it's usefulness.
Most of our customers require tin when the environment is corrosive to silver and in some instances up-charge it over silver due to this characteristic. It is also called for when solderability is a necessity as matte tin.
Generally speaking, tin is available as bright and matte. Bright tin as it's name calls out has an outstanding luster. This is a preferred coating over bus bar, connectors, terminals and switching components. Tin can be plated over a variety of substrates including steel, brass, silver, nickel and aluminum (with pretreatment)
Bright tin can be soldered, however, matte tin is preferred as the organics in bright tin can cause the reliability of soldering to falter. When zinc is in the alloy (as in brass) copper or nickel underplating is recommended as an undercoat to prevent the zinc from migrating into the tin deposit. See keeping tin solderable
The solderable nature of tin diminishes over time as tin oxidizes so it is important to keep tin with the intention of being soldered covered. This has the capability of significantly extending the life of matte tin solderability. Likewise, it is advised to put the material to use quickly due to the perishable nature of the solderability.
Technical Plating is able to bake hardened tin plated steel parts to facilitate hydrogen embrittlement relief
Tin Plating Over Aluminum
Tin Plating over aluminum substrates is generally specified when alternatives to the more expensive copper are sought after. Plating on aluminum is perhaps one of the more challenging subsets of plating due to aluminum's propensity to form oxides almost immediately when exposed to oxygen. TP has a lot of experience plating on aluminum substrates.
Technical Plating offers both bright and matte electrolytic acid tin over most substrates (including aluminum) in the following formats in both rack and barrel applications.
Class A .0001" min, mild service, significant surface shielded from atmosphere
Class B .0002" min, mild service, exposed significant surface
Class C .00032" min, nonferrous, .0004" ferrous, moderate service
Class D .0006" min, nonferrous, .0008" ferrous, severe service
Class E .0012" min very severe service
Class F .00006" min mild service conditions for short shelf life & contact applications
Class I: Electrolytic (Thickness per ASTM duty)
In-house developed Standards
Technical plating is able to offer baking of hardened steel parts to facilitate stress relief