How Does Plasma Thermal Spray Work?
Generally, plasma thermal spray is used to create a high-quality coating on a variety of materials. It can be applied to ceramics, metals, alloys, and other materials. Its advantages include the ability to apply a thin coating, exceptional bond strength, and minimal substrate distortion. It is also very versatile, which makes it ideal for a wide range of applications.
The process involves a high-temperature plasma jet, which is created by combining gas mixtures. The heat of the mixture increases quickly to produce a 14,000-degree plasma. This high temperature is not only helpful in the deposition of a variety of materials, but it also allows for the spraying of high-melting-point materials. Typical applications for plasma spray include aerospace, medical, automotive, and industrial equipment. For more information on Thermal Plasma Spray applications, visit https://www.poeton.co.uk/advanced-treatments/apticote-800-thermal-plasma-spray
To perform the plasma spray process, the coating material is fed into a plasma jet. This feedstock is typically powder, but can be liquid. A variety of gases are used, such as hydrogen gas, nitrogen, argon and helium. These gases are mixed in a way that allows for a precise pressure. The combination of the high heat and the low pressure helps to ensure that the coating does not cause any damage to the substrate.
The plasma jet is initially heated to a high temperature by a DC arc, which forms between the cathode and anode of the plasma gun. This ionisation of the plasma gas causes molecular dissociation. The gas then flows past the arc, blowing arc plasma out through the nozzle. The resulting gas stream sprays molten metal onto the substrate. The molten metal is then cooled and solidifies to form a strong bond with the surface.
The high particle velocities of the plasma spraying process help to improve adhesion and increase densities of the coating. The sprayed particles flatten on the surface, increasing the contact angle. The sprayed droplets interlock on top of each other, creating a protective coating. It is important to use a regulated working environment for the process.
Plasma spraying is a highly effective technique for repairing equipment. It works well for food grade equipment, nonstick surfaces, and machines that require high conductivity. The process also produces a durable coating, making the sprayed materials last longer.
Another advantage of plasma spray is that it can be done in a controlled atmosphere. This helps to avoid potential gas-metal reactions. The plasma jet may be operated in a vacuum chamber or an ambient atmosphere. These methods eliminate the potential for gas-metal reactions, which prevents the risk of damaging the substrate. The substrate is cooled to a low temperature, which helps to protect it from the effects of the heat.