Microstructural characterization of PS-PVD ceramic thermal barrier coatings with quasi-columnar structures

Yttria-stabilized zirconia (YSZ) thermal barrier coatings with quasi-columnar structure were produced by plasma spray physical vapor deposition (PS-PVD). To form this typical structured coating, the process-structure relationships response for substrate temperature, carrier gas flow and spray distance were investigated. Furthermore, this study revealed its characterization in coating microstructures. It was found that the substrate temperature played a governor role in determining the formation of quasi-columnar structure partially because it affected the nucleation rate of vapors during deposition. Appropriate carrier gas flow and spray distance were helpful to remove the un-melted particles and droplets from the plasma plume and promote the formation of quasi-columnar microstructure with high-ratio vapors. The quasi-columnar coating is featured with feather-like polycrystal structure with average misorientation angle of ~ 35.4° and average diameter of ~ 1.17 μm.