Thermal plasma spray is a surface coating process that is used to improve the durability, heat resistance, and protection from corrosion of materials. You’ll find it used in industries like aerospace or energy, where parts are pushed to their limits and need that extra layer of protection.
What is Plasma?
At the heart of the process is plasma, a super-heated, electrically charged gas. The plasma can reach temperatures beyond 10,000°C – at that level, most materials don’t stand a chance of staying solid. To create this, a plasma torch uses an electric arc heats to up a gas -usually argon or nitrogen – until it turns into this incredibly hot plasma jet that shoots out at high speed.
The Coating
Once that plasma jet is created, fine powder particles are fed into it. These powders can be metals, ceramics, or other materials, depending on what kind of coating is needed. The heat from the plasma melts these particles almost instantly. In thermal plasma spray, such as at //www.poeton.co.uk/surface-treatments/thermal-metal-sprays/plasma-coatings/, the extreme temperatures involved mean the particles stay fully molten just long enough to spread out smoothly when they hit the surface.
At the same time, the jet is moving so fast that it carries these molten droplets straight toward the surface that is being coated. When they hit the surface, they flatten out quickly.
Because the surface is much cooler, the droplets solidify almost immediately. This happens over and over again, with more and more particles stacking up. Gradually, a coating forms layer by layer until you get a solid finish.