"TixAlyN Coating Manufacturing by Reactive Very Low Pressure Plasma Spraying (R-VLPPS)"

Very Low Pressure Plasma Spraying (VLPPS, 100 – 1000 Pa) is an emerging process allowing manufacturing oxide and metallic coatings coming from a combination of molten and accelerated particles and vaporized material condensation. This paper aims to present recent developments aiming at TixAlyN coating manufacturing via a reactive mode. At first, Nitrogen was used as primary plasma forming gas to enrich spraying surrounding with nitriding species. Plasma jet mass enthlapy and substrate surface temperature were varied to enhance nitride phase formation during spraying. Then, a secondary Nitrogen injection was considered and placed close to the surface to be covered to create a continual Nitrogen supply and then to promote the nitriding mechanisms on the surface. SEM, XRD, GDOES and NHT were implemented to characterize coatings structure. This study details the nitrides formation whith respect to spraying conditions. The microstructural and mechanical features as well as the chemical composition are presented.