Thermal spraying is the term used for the process of adding a coating consisting of fine molten or semi-molten particles onto specific items and surfaces. In this process, the item that the coating is added to is referred to as the ‘substrate’. The coatings can be applied to both metallic and some non-metallic items.
A wide range of materials can be deposited, including metals, ceramics, cermets, and polymers. As long as the substance becomes plastic or melts when heated, it can be used. The coatings that are produced can vary in thickness, most commonly being between 0.1mm and 10mm.
Spray processes
There are six main types of thermal spray processes: wire spraying, powder spraying, electric-arc spraying, detonation gun spraying, High-Velocity Oxy Fuel (HVOF) spraying, and plasma spraying. Each of these has its own unique benefits, but essentially they all work by projecting a high-speed ‘stream’ of the melted particles onto the substrate.
With plasma spraying, compressed gas is ionised in order to create a plasma. This is then heated and blasted at the substrate. How well the coating adheres to the substrate is dependent on the surface condition and preparation of the surface.
The bond that is created using this process is mechanical rather than metallurgical or fused. This is different to other coating processes such as brazing, arc welding, and laser coating.
Applications
Thermal spraying is used across numerous industries for protecting components or equipment and also for reclamation. Thermally-sprayed coatings are used on a vast range of items, including things like diesel engines, pumps, compressors, ball bearings, and even on medical and dental implants.
If you feel that thermal plasma spray could be the solution you have been looking for, there are plenty of expert companies around – many of which have excellent online resources for you to read such as the examples seen at www.poeton.co.uk/advanced-treatments/apticote-800-thermal-plasma-spray.
Thermal spraying has been widely used for several decades, and has numerous advantages, notably the range of coating materials that can be used and the fact that it can be done both manually and mechanically.
