Effect of combined CeO2 and La2O3 additions and powder processing methods on YSZ thermal barrier coatings

Abstract

This study investigates the effect of codoping CeO₂ and La₂O₃ into yttria-stabilized zirconia (YSZ) via two different spray powder preparation methods: mechanical ball milling and spray granulation, followed by the deposition of CeO₂–La₂O₃–YSZ coatings using atmospheric plasma spraying. The phase composition, microstructure, and thermal shock resistance of the composite powders and coatings were analyzed to explore the influence of CeO₂–La₂O₃ codoping and powder preparation techniques on the microstructure and performance of the coatings. The results indicate that the addition of CeO₂ and La₂O₃ enhances the phase stability of YSZ coatings, reduces thermal conductivity, and significantly improves thermal shock resistance. The preparation method of the spray powder affects the morphology of the powder and the solubility of rare earth elements in the YSZ coating. Compared to the mechanical mixing method, the spray granulated CeO₂–La₂O₃–YSZ composite powder exhibits good agglomeration and spherical morphology. After plasma spraying, the rare earth elements are more thoroughly dissolved in the coating, resulting in a uniform microstructure, higher bonding strength, lower thermal conductivity, and better thermal shock resistance. The findings of this study offer valuable insights into the materials design and preparation processes for novel YSZ-based thermal barrier coatings.