Nanostructured Spark Plasma Sintered Ce-TZP Ceramics

摘要

In this work, spark plasma sintering (SPS) of 10 mol% CeO_2-doped ZrO_2 nanocrystalline powders, obtained by a two-step synthesis procedure, allows the preparation of fully densifled nanostructured ceramics. The CeO_2-ZrO_2 powders with particle size below 100 nm are obtained after CeO_2 deposition on hydrothermally synthesized ZrO_2 particles by the impregnation method.Tetragonal CeO_2-ZrO_2 ceramics are obtained when sintering at 1200℃ without holding time. A graded material containing tetragonal, monoclinic, and pyrochlore phases are obtained when sintering at 1200℃ and for 5 min holding time. This is explained in terms of the gradual reduction of Ce~(4+) to Ce~(3+) 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.