Tin plating: processes and application of tinning

Tin plating, an aesthetic and protective treatment for metals

Tin plating for metals is a particular electrolytic immersion treatment applicable to the surface of any metal or metal alloy. This coating operation protects metals from corrosion caused by atmospheric agents, water and some types of food.

Because of this, its field of application is very broad. The properties conferred by tin electroplating include high corrosion resistance, a pleasant appearance (determined by the alloy) and excellent electrical conductivity.

Tin film has a low porosity, since porosity could cause quicker oxidation in less noble metals such as iron. The purpose of tinning is precisely to reduce this property.

Another important feature from a functional point of view is the optimal preparation of the surface for possible painting.

Acid baths and alkaline baths, two types of tin plating

Tin coatings can be applied using two different methods: immersion in acidic baths or alkaline baths.

In the first case, a stannous compound (divalent tin) is used, while in the second case, a stannic compound (tetravalent tin) is used. The result is that the electrochemical solution in acidic baths is double the solution in alkaline baths. This leads to a higher current efficiency for acidic baths and a faster plating treatment.

When, instead, a high penetration power is required due to the particular shape of the objects to be plated, alkaline baths are preferred.

The equivalent of tin electroplating in the metal protection systems offered by Impreglon consists of TempCoat® coatings, which ensure excellent non-stick properties, corrosion protection and smoothness. Teflon PTFE and Teflon PFA non-stick coatings also give the surface non-stick properties and resistance to chemical agents.