Phase assembly and electrical conductivity of spark plasma sintered CeO2–ZrO2 ceramics
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Ce x Zr1−x O2 (x = 0.10, 0.16 and 0.33) nanocrystalline powders were obtained by a two-step synthesis technique and sintered by spark plasma sintering (SPS). As consequence of the reduction of Ce4+ to Ce3+ species by carbon in the graphite environment in SPS, phase assemblies including tetragonal, monoclinic and pyrochlore phases were generated in the ceramics during the sintering process. The electrical conductivity was highly dependent on phase assembly and atmosphere (N2, H2 and O2). A significant decrease in the activation energy was noticed in the ceramics with high pyrochlore content when measuring the conductivity in H2 atmosphere, consequence of the strong reduction promoted in these ceramics during the measurement. Equal conduction behavior with similar activation energy was observed in all the ceramics when measuring in O2 atmosphere.
KeywordsCeO2–ZrO2 Spark plasma sintering Pyrochlore Electrical conductivity
Dr. Cruz thanks Junta de Andalucía (TEP-1048) for her fellowship. The financial support for this work has been obtained from the Spanish Ministerio de Ciencia e Innovación (ENE2009-14522-C05-01) and (ENE2009-14522-C05-03). Cofinanced by FEDER funds from the European Union and from Junta de Andalucía (P09-TEP-5454).
- 2.Trovarelli A (2002) Catalysis by ceria and related materials. Imperial College press, LondonGoogle Scholar
- 17.Cruz SA, Poyato R, Cumbrera FL, Odriozola JA (2012) Nanostructured spark plasma sintered Ce-TZP ceramics. J Am Ceram Soc 95(3):901–906Google Scholar
- 21.Omata T, Kishimoto H, Otsuka-Yao-Matsuo S, Ohtori N, Umesaki N (1999) Vibrational spectroscopic and X-ray diffraction studies of cerium zirconium oxides with Ce/Zr composition ratio = 1 prepared by reduction and successive oxidation of t′-(Ce0.5Zr0.5)O2 phase. J Solid State Chem 147(2):573–583CrossRefGoogle Scholar
- 24.Leonov AI, Andreeva AB, Keler EK (1966) Influence of the gas atmosphere on the reaction of zirconium dioxide with oxides of cerium. Izq Akad Nauk SSSR Neorganicheskie Mater 2:137–144Google Scholar
- 25.Rodriguez-Carvajal J (1990) FULLPROF: a program for Rietveld refinement and pattern matching analysis. In: Abstracts of the satellite meeting on powder diffraction of the XV congress of the IUCr, pp 127–130Google Scholar
- 28.Pecharsky VK, Zavalij PY (2009) Fundamentals of powder diffraction and structural characterization of materials, 2nd edn. Springer, BerlinGoogle Scholar