Abstract

Suspension plasma spraying (SPS) is a rising coating technology producing fine nanostructured coatings with promising mechanical and physical properties while taking advantages of the well-established Atmospheric Plasma Spray (APS) process. Anelastic behavior of the coatings can be a specific identifier of their mechanical behavior which is related to the strength of coatings interlayers bonding and defect architecture. To better understand the relationship between SPS conditions and anelastic responses, post-deposition characterization technique under multiple thermal cycles using ex-situ coating property (ECP) sensor, which is based on thermal mismatch strain of coating-substrate system is applied. This technique makes it possible to determine the elastic modulus, non-linear degree and hysteresis degree of the spray coatings through the curvature-temperature response in a dependable and repeatable way. In this work, suspension plasma-sprayed YSZ ceramic coatings are produced under different spray conditions, and their anelastic characteristics are compared. The results show that the samples coated in high plasma power condition have a higher elastic modulus at low strain which is attributed to better inter-splat/inter-layer bonding due to higher particle impact velocity and temperature. However, samples produced in low raster speed condition have a relatively lower elastic modulus and higher compliance at an elevated temperature which describes the higher flexibility of these coating at higher temperature. These results make it possible to better understand the relationship between sprayed coating microstructures and mechanical properties in SPS coatings.