NiCrAlY Coatings in YAG Laser Combined Low Pressure Plasma Spraying

Densification of plasma-sprayed NiCrAlY coatings was studied from the viewpoint of hybrid spraying combined with YAG laser irradiation. The laser beam was varied while performing low pressure plasma hybrid spraying and the microstructure of each coating was examined and compared with a conventional plasma sprayed coating. Of the various hybrid spraying methods tested, simultaneous irradiation produced the hardest microstructure with the least amount of porosity. The characteristics of the microstructures observed in each coating are explained with respect to their thermal hysteresis behaviors.