Effect of the introduction procedure and concentration of yttrium cations on the crystal structure of (1–x)ZrO2 · xY2O3 powders

Resumo

An integrated study of the crystal and local structures of complex oxides (1–x)ZrO₂ · xY₂O₃ (x = 0.005–0.18, YSZ), precipitated from solutions of metal salts and annealed in air, was carried out. For the use of deposition from solutions, reverse co-precipitation was found to be the method of choice for introducing yttrium cations into YSZ, ensuring the maximum stabilization effect of high-temperature phases. An increase in the yttrium content induces polymorphic transformations, monoclinic phase (P21/a) → tetragonal phase (P4₂/nmc) (for x = 0.02) → cubic phase (Fm\(\bar 3\)m) (for x = 0.08), in the samples prepared at temperatures of ≤1000°C. A Raman study of the local structure of YSZ powders confirmed the formation of a single-phase tetragonal structure for the 2YSZ and 3YSZ samples and identified trace amounts of the tetragonal phase for the 8YSZ and 18YSZ samples with the cubic structure.