Abstract
The aim of this study is to understand how the characteristics of feedstock powders impact the morphology of thermal spray coatings. In the experiments, YSZ powders were prepared, characterized, and deposited on nickel-base superalloy substrates by plasma spray physical vapor deposition (PS-PVD) and the coatings were examined and tested. The results indicate that particle size distribution is an important factor in coating quality and that very fine-grained powder (< 12 µm) is not conducive to the formation of a columnar crystal structure. A powder with a rough, porous structure, on the other hand, readily absorbs heat and is thus easily vaporized, leading to a good columnar structure in the coating. In contrast, dense powder is difficult to vaporize, which promotes the formation of layered structures. Among the coatings with a columnar structure, one produced from powders with a particle size of 16.7 µm exhibited the lowest porosity and highest microhardness.
