Thermal spraying
Group of coating processes in which feedstock materials in wire or powder form are melted and propelled at high velocities onto the prepared surface.
In thermal spraying, the filler material (powder or wire) is melted and propelled at high velocity onto the surface. The base material is not melted; the coating adheres mechanically and by diffusion to the roughened surface. You get a hard, wear-resistant layer that can also provide corrosion protection. Make sure the surface is clean, grease-free, and roughened – otherwise the coating won't hold. If you don't set the parameters (distance, feed rate, temperature) properly, the coating will be porous or will peel off. Don't overdo the coating thickness, or too much stress will build up and cause cracking.