There are a number of different thermal spraying techniques – with plasma spray perhaps being the most popular.
What is plasma spraying?
Plasma spraying is one of a number of coating techniques that come under the bracket of ‘Thermal’. This essentially means that they utilise heat.
How does it work?
Plasma spraying works by melting a coating material (in powder form), and spraying molten droplets at high velocity at the item that is to be coated (referred to as the ‘substrate’).
What are the stages of the process?
There are a number of key stages in the plasma spray process. The initial stage is preparation/preheating, followed by the injection of the fine powder particles into the plasma jet.
The next step involves propelling the molten droplets toward the substrate at very high (even supersonic) velocities. As these hit the substrate, they solidify and bond with each other, resulting in a coating layer.
The final stage is cooling and solidification
What materials can be used as coatings?
The range of materials that can be used includes metals, ceramics, composites, and polymers. Each of these offers a unique set of attributes. For example, if corrosion resistance is the key requirement, then stainless steel, titanium, or aluminium can be used.
What are the benefits?
The key benefits of plasma spray are its versatility in terms of what it can be used on, the range of materials that can be used as coatings, and the fact that it can add or enhance a number of desirable qualities to an item.
Plasma spray experts
There are several firms in the UK that specialise in thermal spray coatings. Many of these have useful online resources such as the examples seen here: www.poeton.co.uk/standard-treatments/plasma-coatings/.
What items can be sprayed?
Plasma spray coatings can be applied to objects of almost any size. Plasma spray coated items are found in numerous industries. Examples of items that may be coated using plasma spray include hair straighteners, car parts (piston rings, bypass shafts, and carburettor parts), medical and dental implants, and solar panels.
