Nanostructured Spark Plasma Sintered Ce‐TZP Ceramics

Abstract

In this work, spark plasma sintering (SPS) of 10 mol% CeO2‐doped ZrO2 nanocrystalline powders, obtained by a two‐step synthesis procedure, allows the preparation of fully densified nanostructured ceramics. The CeO2–ZrO2 powders with particle size below 100 nm are obtained after CeO2 deposition on hydrothermally synthesized ZrO2 particles by the impregnation method.Tetragonal CeO2–ZrO2 ceramics are obtained when sintering at 1200°C without holding time. A graded material containing tetragonal, monoclinic, and pyrochlore phases are obtained when sintering at 1200°C and for 5 min holding time. This is explained in terms of the gradual reduction of Ce4+ to Ce3+ species by carbon in the graphite environment during SPS. With the successful combination of the stabilizer coating technique and SPS, we achieve not only the stabilization of the tetragonal phase in the ceramics, but also good control of the grain size, by producing nanostructured ceramics with 40–70 nm grain sizes.