The influence of spraying parameters on in-flight characteristics of tungsten particlesand the resulting splats sprayed by hybrid water-gas stabilized plasma torch

摘要

Tungsten particles were sprayed by a novel plasma torch with hybrid water-gas stabilization (WSP?-H). Severalspraying parameters were varied - arc current, argon flow rate, carrier gas flow rate and spraying distance. Thetemperature and velocity of the individual particles were monitored by the DPV 2000 optical sensor. Individualsplats were collected on polished stainless steel substrates and analyzed by SEM to assess their melting, flatteningand/or fragmentation. These features were correlated with the basic in-flight particle characteristics and conditionsfor production of dense coatings were sought for. Significant dependence of the splats morphology on sprayingparameters was found, and important improvement of particle melting at WSP?-H over conventional water stabilizedplasma torch (WSP?) was registered.