Microstructural Characterization and Room Temperature Erosion Behaviour of As-deposited SPS, EB-PVD and APS YSZ-based TBCs

The erosion behaviour at room temperature of as-sprayed SPS, EB-PVD and APS YSZ-based TBCs was investigated. All coatings were deposited on Inconel 625 alloy coupons. A single APS CoNiCrAlY bond coat was employed for all SPS and APS TBCs. The EB-PVD YSZ TBC was provided by a 3^rd party (independent EB-PVD TBC industrial provider). The erodent material was alumina and the impact angles were 15^o and 90^o. A total of 4 different types of SPS YSZ-based TBCs were tested, which consisted of two distinct columnar-segmented and two distinct columnar-sprouted microstructures. Two of the SPS TBCs were sprayed by the NRC; whereas, the other two sprayed by an independent industrial thermal spray torch manufacturer. The EB-PVD and APS YSZ TBCs were employed as benchmarks. The erosion performance of the different TBCs in this study was ranked based on coating volume loss after wear testing. The TBC microstructures and phase compositions were evaluated via SEM and XRD. The erosion mechanisms of the different TBCs were compared by analyzing the cross-sectional microstructures of the as-sprayed and eroded TBCs. These results were originated from the Surftec Industrial R&D Group of the NRC.