In this study yttrium stabilized zirconia (YSZ) spray dried granules are produced and applied for thermal barrier coatings in gas turbine applications. The morphologies of the spray dried granules are varied by the control of the solvent type, binder/ dispersant content and process parameters during spray drying. The feed rate depends on the morphologies of the granules. The spray dried granules are deposited over a NiCrCoAlY bond coat by an air plasma spray coating apparatus for the thermal barrier coatings. We evaluated the thermal tolerance of the thermal barrier layers by thermal annealing tests and hardness tests after the thermal annealing tests. As a result, the thermal barrier coating using pre-heat treated spherical powder gave advantages in thermal and mechanical resistances after the thermal annealing test.

Keywords: Thermal barrier coating, Spray drying, Thermal and mechanical property.