Yttria-Stabilized Zirconia Deposited Using Suspension Plasma Spraying: A Comparative Framework with Electron Beam Physical Vapor Deposition and Air Plasma Spraying

Emerging technological advancements are aimed at improving the operating temperatures of gas turbine engines to improve their overall efficiency. This has triggered the development of yttria-stabilized zirconia-based thermal barrier coatings (YSZ TBC) with microstructures designed for enhanced performance achieved by optimizing process parameters and deposition techniques. The present study aims to evaluate the performance of YSZ columnar structure deposited using suspension plasma spraying (SPS) on Pt-Al bond-coated CMSX-4 single-crystal nickel-based superalloy substrate, reported for the first time in the literature. The thermal cycling performance and calcium-magnesium-alumino-silicate (CMAS) corrosion behavior of SPS YSZ coatings were compared with YSZ deposited using electron beam physical vapor deposition (EBPVD) and air plasma spraying (APS) techniques. It was observed that SPS YSZ coatings showed the highest thermal cycling resilience when compared to EBPVD and APS. In addition to this, the CMAS penetration was also substantially lower in SPS YSZ coatings compared with EBPVD and APS coatings. Unlike SPS and EBPVD coatings, APS coatings also showed signs of tetragonal-to-monoclinic phase transitions in some regions away from the top surface. These observations lay the baseline for the potential development of optimized microstructures using the SPS deposition technique with improved performance relevant to the TBCs.