What is galvanisation?
Galvanisation or galvanization (or galvanizing as it is most commonly called) is the process of applying a protective zinc coating to iron or steel, to prevent rusting. The most common method is hot dip galvanizing, in which steel sections are submerged in a bath of molten zinc.
Galvanization helps extend the life of steel parts by forming a membrane between the metal and the air, preventing the accumulation of iron oxide on the steel layer. Galvanization also offers superior corrosion resistance to environmentally exposed parts.
Steps involved in the process
The galvanizing process consists of three basic steps, namely
- Surface preparation
- Fuxing
- Galvanizing.
Material is loaded onto jigs before being immersed in molten zinc at about 450 degrees until the working temperature is the same as zinc. During this process, the molten zinc reacts to a series of zinc/iron alloys with the steel surface.
What is Electroplating?
Electroplating is the process of depositing metal onto a surface through electrolysis or chemical reduction of an alloy. This is accomplished using an electroplating apparatus that includes a brine solution, a battery, wires, and alligator clips that hold carbon rods attached to the metal to be electroplated and the metal to be layered.
The term “electroplating” may also be used occasionally for processes that use an electric current to achieve oxidation of anions on to a solid substrate, as in the formation of silver chloride on silver wire to make silver/silver-chloride electrodes.
Electroplating process is influenced by a variety of factors. Some of these factors include the electrodes’ surface area, temperature, the type of metal and electrolyte used, and the magnitude of the applied current.
Applications of Electroplating
- Aesthetics
- Commercial applications
- To prevent corrosion
- Conduction of Electricity
- Reduce friction
- To protect from radiation
- Improving the thickness of the metal surface.
- Enhancing the electrical conductivity like plating a copper layer on an electrical component.
- Improving surface uniformity.
Galvanisation vs Electroplating
| GALVANISATION | ELECTROPLATING |
| It is also referred to as Zinc coating. | It is also referred to as Electro-deposition. |
| Galvanization is a metal finishing process that creates a surface layer of zinc on iron or steel. | Electroplating is the process of depositing metal onto a surface through electrolysis or chemical reduction of an alloy. |
| Galvanization uses molten zinc metal. | Electroplating uses, Zinc, chromium, gold, rhodium, copper, tin, nickel or silver. |
| Galvanization is done by dipping the base metal or piece into a molten bath of zinc. | Electroplating is done by use of electricity whereby a thin layer of zinc, copper or silver is applied to the base metal. |
| Galvanization increases the strength of the metal, however, it has been criticized for being toxic as well as damaging other metals that come into contact with it. | Electroplating increases the hardness of the metal without affecting its surface finish or machinability. |
| Galvanization is less time-consuming. | Electroplating is time consuming. |
| Galvanization produces smoother surface than electroplating. | Electroplated surfaces are not as smooth as galvanized surfaces. |
| Galvanization is mainly done for corrosion resistance. | Electroplating can be used for decorative purposes, corrosion resistance, wear resistance, improving mechanical properties etc. |
| Galvanization is often used in the making of parts for cars, airplanes and other components that are made from steel. | Electroplating can be used for aesthetic purposes, reduction of friction, radiation protection, corrosion resistance and other commercial applications. |