Abstract

Sprayed coatings produced with submicron particles have unique properties when compared to 10-100 micron particles. Suspension Plasma Spray (SPS) is used to deposit coatings from submicron particles. This process, which is a modification of the atmospheric plasma spray (APS) process, uses a liquid carrier to inject the fine particles into the plasma jet. However, this technique is still subject of extensive research efforts due to the complexity of the phenomena related to the liquid stream and the submicron particles in contact with the plasma jet. There is a wide range of parameters that affect the properties and microstructure of the coatings sprayed using SPS.
In this study, the influence of the substrate shape on the resulting coating microstructure is investigated. For this purpose, an yttria-stabilized zirconia (YSZ) suspension was sprayed on flat and curved stainless steel substrates by SPS. The suspension was composed of 20 wt.% YSZ particles in ethanol. After spraying, the morphology of the coatings has been characterized by scanning electron microscopy (SEM). The results showed that the substrate shape influences the amount of coating material deposited and column growth. The amount of coating material deposited was seen to decrease as the radius of curvature decreased. Finally, roughness influences the formation of columnar structure.