| Abstract: |
Versatile properties of WSP-H plasma gun with combined stabilization of electric arc by water steam and argon gas are presented. The hybrid water/gas stabilization allows to adjust steam/argon ratio and thus change the plasma jet properties from high-enthalpy low-density plasma typical for liquid stabilized guns to lower enthalpy higher density plasmas typically generated in gas stabilized guns. Recently, a self-adjustable powder injecting system was developed to increase efficiency and repeatability of the hybrid-WSP spraying process. Several ceramic powder materials (including alumina, mullite, YSZ) were plasma sprayed by the hybrid-WSP gun at high feed rates ranging from 150 to 400 g/min. Temperature and velocity of the molten particles in-flight were measured by DPV-2000 and statistically evaluated for different plasma jet properties and feeding rates. The DPV measurements results were related to the properties of the sprayed coatings including porosity, microhardness, adhesion strength, and phase composition and also compared with typical results achieved by gas stabilized plasma guns. Finally, deposition efficiency was evaluated according to EN ISO 17836 for the different spraying conditions.
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