Common types of metal coating to know
Metal coatings are a way to protect a surface to improve its resilience and reduce the risk of corrosion. Depending on the type of metal and its purpose, which form of coating is most appropriate varies. Here are some common kinds.
Paint Coating
As the name suggests, a layer of liquid paint is used. It is a less durable method, but it is also quicker and more cost-effective. Some paints contain dangerous toxins.
Powder coating explained
Powder Coating
Powder is applied through an electrostatic method to create a durable and aesthetically pleasing coat. It can save money in the long term, but short-term costs are higher. Thin coats are very difficult.
Electroplating
A layer of metal is attached to the surface with the help of an electrolytic solution and an electric current. This can enhance the properties of the surface metal. It is aesthetically pleasing, but the coat is not always evenly spread (electroless plating is an alternative).
Galvanising for durability
Galvanising
Iron or steel is submerged in molten zinc and then removed to cause a reaction with carbon dioxide and oxygen in the air. This creates a stable, durable, protective zinc sulphide coating. Unfortunately, this is expensive, and the resulting surface can look dull and unpleasant.
This is most effective with aluminium and is not suitable for all metals. Surfaces are placed in an electrolytic solution with a cathode. An electric current oxidises the aluminium. The coating is stable, non-toxic and easy to maintain.
Thermal spray for thick coatings
Thermal Spray
Thermal spray uses heat to apply an extra thick coating. It may be a thermal plasma spray, as can be seen at poeton.co.uk/advanced-treatments/apticote-800-thermal-plasma-spray/, or a wire arc spray.
When you have a metal surface that needs coating, you need to consider all the available options to choose the most suitable one for your needs.
Summary
Runs through common metal coating methods and how they compare: paint coating is quick and cost-effective but less durable, powder coating gives a durable finish at higher short-term cost, electroplating and electroless plating add a metal layer for aesthetics, galvanising creates a durable zinc coating, anodising suits aluminium, and thermal spray applies an extra-thick protective coating.
Questions this article raises
- Which metal coating method offers the best long-term value for money?
- How do you choose the right coating for a specific type of metal?
- What are the environmental considerations of these different coating processes?
