Question

Write a short note on: Tinning.

Answer 1

Hint: It is a process often done to prevent a metal from the air. For the coating, a group 14 element is used.

Complete step by step answer:
As the name suggests, tinning is the process of coating sheets of wrought iron or steel with tin, and the final product is known as tinplate. This is often done to prevent rust. Also, ends of wires are tinned to prevent their oxidation. Oxidation of wires can increase their electrical resistance. The term tinning is also used for different processes of coating a metal with solder before soldering. Nowadays, tinplate is used to manufacture tin cans. Tinplate was also used to manufacture tinware, which are pans, pots and other hollowware. There are two processes for tinning, hot-dipping and electroplating.

Hot-dipping: In this process, tinplate is made by cold rolling steel or iron. Cold rolling is the process by which the sheet metal is introduced between rollers and then compressed and squeezed. It is followed by pickling to remove any scale, annealing to remove any strain hardening, and then coating it with a thin layer of tin.

Electroplating: In this process, tinning is done by electroplating. The item to be tinned is kept in a container containing a solution of tin salts. The apparatus is connected to an electrical circuit, which forms the cathode of the circuit. Anode is of the same metal that is to be plated. Metal ions are attracted to them when a current is passed through the circuit. Thus our metal is electroplated.

Note: Remember that galvanization is different from tinning. In galvanization, Zinc is coated on the metal while in tinning, Tin is coated on the metal.