• hvof_parmaspray
  • polveri
  • riporti_parmaspray

Plasma Spraying

In plasma spraying process, the feedstock — typically as a powder, sometimes as a liquid, suspension or wire — is introduced into the plasma jet, emanating from a plasma torch. In the jet, where the temperature is on the order of 10,000 K, the material is melted and propelled towards a substrate. There, the molten droplets flatten, rapidly solidify and form a deposit.
Commonly, the deposits remain adherent to the substrate as coatings; free-standing parts can also be produced by removing the substrate.
The deposits consist of a multitude of pancake-like ‘splats’ called lamellae, formed by flattening of the liquid droplets. As the feedstock powders typically have sizes from micrometres to above 100 micrometres, the lamellae have thickness in the micrometre range and lateral dimension from several to hundreds of micrometres.
This technique is mostly used to produce coatings on structural materials. Such coatings provide protection against high temperatures (for example thermal barrier coatings for exhaust heat management), corrosion, erosion, wear; they can also change the appearance, electrical or tribological properties of the surface, replace worn material.