Two new inner contours of de Laval nozzles (V70, V21) for F4 torch, which have already successfully been establishedfor the Atmospheric Plasma Spraying (APS) are investigated for application under Vacuum Plasma Sprayingconditions (VPS). Studies have been performed with regard to power efficiency, sound level and arc voltage fluctuationsas well as coating quality and deposition efficiency for use of CoNiCrAlY powder as feedstock material.The results are compared to the commonly used standard VPS nozzle. CFD calculations and enthalpy probemeasurements of plasma gas velocity and temperature distribution in the centreline of the supersonic plasma jetsare carried out in order to get insight in the basic dependencies.
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