When it comes to choosing the right type of thermal spray coating for your application, it makes sense to take the time to weigh up your options. With many excellent types of coating available, you will be sure to find the ideal solution for your needs.
Types of thermal spray coatings
The category of thermal spray coatings can be broken down into five main types: flame, arc, plasma, HVOF (high-velocity oxy-fuel), and detonation gun spraying. All these coatings require a consumable, such as a powder or wire, to be heated to a high temperature and then projected onto the surface to be coated. The difference in these five approaches comes from the heat source and the speed at which the coating particles hit the substrate’s surface.
Flame spraying, for example, uses heat drawn from the burning of a fuel gas and oxygen mixture. This heats the chosen consumable so that it can be projected via compressed air or inert gas. The result is an inexpensive spray coating that offers less durability and lower bond strength than other approaches. HGOF uses a comparable heat source but delivers higher particle velocities, leading to far superior coatings.
Arc spraying is achieved by placing a DC electrical arch between a pair of consumable wire electrodes. When these electrodes melt, the spray substance is created and then projected via compressed gas. The resulting coating has a higher bond strength than flame coatings; however, this method produces unwanted side effects, such as fumes.
The best choice
Also using a DC electric arc, thermal plasma spray coating offers a better solution. A powder consumable is fed into a jet whilst an inert gas is fed into the torch, resulting in a high-velocity spray with particles achieving speeds of 200-300m/s. This technique achieves a strong and effective coating of substrates with high melting points.
Companies such as Poeton can deliver variations of this application, such as VPS (vacuum plasma spraying) and LPPS (low-pressure plasma spraying), to enable a vast selection of items to be durably coated. The popularity of this type of coating can be seen by the growing value of its market.
Detonation gun spraying is another great option, using shockwave technology to produce high particle speeds and superb quality coatings.