Phase assembly and electrical conductivity of spark plasma sintered CeO sub(2)-ZrO sub(2) ceramics

• Published in: Journal of materials science Vol. 49; no. 18; pp. 6353 - 6362
• Main Authors: Poyato, Rosalia, Cruz, Sylvia A, Cumbrera, Francisco L, Moreno, Berta, Chinarro, Eva, Odriozola, Jose A
• Format: Journal Article
• Language: English
• Published: 01-09-2014
• Subjects: Assembly; Atmospheres; Ceramics; Electrical resistivity; Reduction; Resistivity; Sintering; Spark plasma sintering
• ISSN: 0022-2461; 1573-4803
• DOI: 10.1007/s10853-014-8361-6

Ce sub( x )Zr sub(1-x )O sub(2) (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 Ce super(4+) to Ce super(3+) 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 (N sub(2), H sub(2) and O sub(2)). A significant decrease in the activation energy was noticed in the ceramics with high pyrochlore content when measuring the conductivity in H sub(2) 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 O sub(2) atmosphere.