Processing and Suspension Plasma Spray Deposition of ZrO₂-Based Ceramic Materials for Thermal Barrier Coatings

This work focuses on the processing and deposit by suspension plasma spraying (SPS) of ZrO₂-based ceramic materials for Thermal Barrier Coatings (TBC's) applications. The system of interest is ZrO₂-16mol%Y₂O₃-16mol%Ta₂O₅ (16YTZ). This ceramic has been reported to keep a non-transformable tetragonal phase (t'-phase), suitable to overcome the thermodynamic limits of the mostly used conventional 7-8wt.% yttria stabilized zirconia (YSZ). The research consists into evaluate the t'-phase stability and performance of the 16YTZ SPS coating. Synthesis of 16YTZ and, the evolution of the resulting microstructure in the dense ceramic and in the coating are a central part of the study. Sintering behavior in dense ceramics prepared from both precursor derived and milled powders is evaluated. Microstructural characterization by XRD, SEM and RAMAN spectroscopy of the as-deposited ceramic coating is presented and discussed.