Plasma Spray Coatings
Plasma spray coating is a thermal spraying process used to create enhancing coatings on the surface of a substrate material. This coating technique uses a plasma jet to melt coating materials and spray them at high velocities. As large quantities of high energy coating particles collide with the substrate material, they collect on the surface of the substrate to form coating layers. Plasma spraying provides exceptional coatings for the highest level of protection.
The plasma spraying technique differs from other thermal spraying processes in the way that particles are heated and accelerated. The primary tool used in plasma spray coating is the plasma torch. Within the plasma torch, electric arcs are formed between a cathode and anode as a carrier fluid flows around them. The carrier fluid, often oxygen, nitrogen, helium or hydrogen, passes through the electric arcs where it is super heated, forming a plasma flame which projects out of the torch as a plasma jet. In the plasma jet, the temperature can exceed 15,000 K (more than 26,500 F). The coating material, or feedstock, is fed into the plasma jet to be melted and accelerated from the torch. The molten coating particles impact the surface of the substrate material, causing them to flatten and quickly solidify. As thousands of these solidified droplets, or “splats”, adhere to the substrate, they begin to cover the entire surface of the substrate, creating a coating. For thicker coatings, multiple passes can be made over the substrate or the spray can be applied for a longer duration to create additional layers. Once a coating is created, the deposits can be altered and machined to the specified dimensions.
For industrial applications, plasma spraying creates reliable, high quality coatings. Coatings generated using this technique provide excellent abrasion and wear resistance, corrosion resistance, and erosion resistance. They are also great for protecting parts from high temperatures, since thermal conductivity is typically very low. When compared with many other thermal spray coating techniques, plasma spraying produces much higher temperatures and spraying velocities. Higher temperatures open up the possibility to spray refractory materials, which makes this process incredibly useful for coating products used in high temperature applications. Additionally, the quality of the coating typically improves with higher particle velocities. Due to the coating quality and level of protection provided, plasma spray coating is commonly used on aircraft components, agricultural equipment, mining machinery parts, pump components, and engine components. The plasma spray coating process can be accomplished quickly while maintaining high quality, so, for enhanced product performance and protection, plasma spray coating is an efficient, high quality, and economical solution.