SINTERING OF A PLASMA-DERIVED ZIRCONIA POWDER FOR SOLID OXIDE FUEL-CELL ELECTROLYTES

IR GIBSON*, EE LACHOWSKI, John Thomas Sirr Irvine, GP DRANSFIELD

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

8 Citations (Scopus)

Abstract

Gas-phase synthesised zirconia powders with yttria additions provide an attractive alternative to conventional co-precipitated powders as a route to zirconia ceramics. Ceramics produced from such powders show improved resistance to hydrothermal ageing [1]. Here we have compared sintering behaviour of a gas phase derived 8 mol% yttria-stabilised zirconia (Tioxide) with a coprecipitated 8 mol% (Tosoh) material. Phase development as a function of sintering/reaction has been studied by X-ray diffraction, ac impedance and electron optical techniques. As sintering temperature was increased the expected transformations from monoclinic to tetragonal to cubic zirconia were observed; however, in gas-phase derived zirconia ceramics two cubic phases were observed at about 1200 degrees C. Most of the grains (90-95%) contained 8 mol% Y2O3, the expected composition, whereas the minority cubic phase, which disappeared on further heating, contained about only 3 mol% Y2O3. For samples sintered at 1500 degrees C, bulk conductivities, measured at 1000 degrees C, were 5.5 Sm-1 and 10 Sm-1 for co-precipitated and gas-phase derived samples, respectively. Both exhibited a similar activation energy and showed little evidence of grain boundary resistance above 500 degrees C. The influence of phase development sequence upon electrical properties and structural stability is discussed.

Original languageEnglish
Pages (from-to)265-270
Number of pages6
JournalSolid State Ionics
Volume72
Publication statusPublished - Sept 1994
Event9th International Conference on Solid State Ionics - THE HAGUE, Netherlands
Duration: 12 Sept 199317 Sept 1993

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