The process of galvanisation
The process of galvanisation applies a protective coating of zinc onto the metal. This type of coating is commonly used on steel or iron in order to prevent rusting. Galvanisation prevents a ferrous item from rusting, as the corrosion resistance of zinc is much higher than that of steel or iron. Advantages of galvanisation are that it is relatively cheap and easily applied. It also has a very long life and needs little maintenance.
Hot dip galvanisation
Hot dip galvanisation is the most common method of galvanisation. The steel part is submerged in a bath of molten zinc, coating the component with a layer of zinc. Hot-dip galvanisation produces a grey, matte coating to the surface of the metal, which is very thick and durable.
Galvanisation can also be achieved using electrochemical and electrodeposition processes. Electroplated coatings are generally less durable and not really appropriate for outdoor applications because the deposit is very thin. This can be helped by painting the surface of the component, which slows down zinc consumption, delays the corrosion and extending its durability.
The advantage of electroplating is that it is much cheaper than hot dip galvanising. It is used for many different outdoor applications but despite looking good when it is new, it isn’t very durable and won’t withstand the elements very well.
Although galvanisation is cheaper, the final finish isn’t as attractive or durable as some other types of metal finishing. Electroless nickel plating can be used as an alternative to galvanisation as it is durable and aesthetically pleasing.
Electroless nickel plating can also be used in harsh environments because of its high corrosion resistance. The uniform coating created by this process can be a perfect solution for critical high-end engineering items such as those used in the defense, healthcare, automotive and aerospace industries.
Considering the extent of its durability and the attractive finish it creates, electroless nickel plating is cheaper than you might think. It is also the ideal plating for a surface exposed to friction and wear, which can also be increased by using heat treatments.