Microstructure, Mechanical and Thermal Properties of Yttria-Tantala-Stabilized Zirconia Coatings Prepared from Suspension Plasma Spraying

This study focuses on the development of innovative solutions of new material coatings using plasma spraying for Thermal Barrier Coating applications (TBC). The purpose of this work is to explore the feasibility of generating an in-situ ZrO₂-YO_1.5-TaO_2.5 (YTZ) system in the t'-phase during the deposition process of a mechanically activated oxide mixture of the ternary system by Suspension Plasma Spraying (SPS). The oxide mixture compositions and plasma spraying parameters were varied to study their effects on the amount of YTZ t'-phase as well as their corresponding physicochemical properties. Characterization of the coatings was carried out by X-ray diffraction (XRD), scanning electron microscopy (SEM), microhardness (HV), and thermal conductivity which was measured by laser flash analysis. The results show that the coating properties are strongly affected both by the spray distance and the ratio of the gases that promote plasma formation.