ID 229

Zirconia Suspension Spray with Coaxial Twin-Fluid Atomizer for Twin Cathode Plasma Spray Gun

 

Abstract:

Thermal Barrier Coating (TBC) is necessary to increase turbine inlet temperature of a high efficient gas tur-bine for a power station. The atmospheric plasma spraying is employed to process a well-established technolo-gy in the field of surface coating. Suspension plasma spraying is expected to have higher flexibility in particle size of processed material than conventional plasma spraying. Therefore microstructural feature of coating by can be varied by the parameters of suspension plasma spraying, such as molten droplets of material. AIST is trying development of the axial feeding type of suspension plasma gun with thin coaxial twin fluid atomizer. Atomization of ethanol suspension of solid particles is one of the important factors controlling the coating qual-ity. Therefore the spray of zirconia-ethanol suspension from the thin coaxial twin fluid atomizer with new p-torch was investigated. The inner diameter of the inner tube is 0.2mm. Air and argon gas are used as atomizing gas. Sauter Mean Diameter of spray of zirconia-ethanol suspension is more stable than those of zirconia-water suspension. Sauter Mean Diameter of spray of zirconia-water suspension is not stable due to deposition of zir-conia particles on the inner wall of the flow path. The wider coaxial twin fluid atomizer was developed for in-crease of suspension flow and preventing clogging of the flow path. The inner diameter of the inner tube is 0.6mm and 0.4mm respectively. Sauter Mean diameter of suspension spray depends on the mass flow rate of argon gas, zirconia concentration and the mass flow rate of suspension.