Abstract
Individual particles of various ceramic materials sprayed by water stabilized plasma torch (WSP) were characterized in flight by an optical sensing device DPV-2000. Temperature, velocity, and diameter of individual particles were measured at the center of particle plume and maps of the particle plume cross-section were acquired as well. Plasma jet and consecutively particle plume of the WSP torch is much larger compared to gas stabilized torches and even larger than the maximum span of the DPV-2000 sensing head. In summary, temperatures of particles varied from 2000 to 2600°C and their velocities from 60 to 140 m/s depending on the powder feedstock cut size, particle density, feeding distance, spraying distance, and feed rate. The last three parameters were varied to study their effect on the particle states and their distribution in the plasma jet and to correlate these results with selected properties of the corresponding coating. Some of the spraying parameter effects are difficult to interpret, nevertheless, general trends have been established.
