Plasma Spraying of Copper by Hybrid Water-Gas DC Arc Plasma Torch

Water-stabilized DC arc plasma torches offer a good alternative to common plasma sources used for plasma spraying applications. Unique properties of the generated plasma are determined by a specific plasma torch construction. This article is focused on a study of the plasma spraying process performed by a hybrid torch WSP500^®-H, which combines two principles of arc stabilization—water vortex and gas flow. Spraying tests with copper powder have been carried out in a wide range of plasma torch parameters. First, analyses of particle in-flight behavior for various spraying conditions were done. After, particles were collected in liquid nitrogen, which enabled analyses of the particle in-flight oxidation. A series of spraying tests were carried out and coatings were analyzed for their microstructure, porosity, oxide content, mechanical, and thermal properties.