Mechanical properties of ceria based oxygen ionic conductors for SOFC

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Abstract

The fracture strength and creep rate of rear earth (Y and Gd) doped ceria are systematically studied from the viewpoints of dopant concentration, oxygen partial pressure and temperature dependences. Fracture strength and creep rate are measured by modified small punch test and four point bending method, respectively. From results of fracture test, the highest fracture strength is obtained on the samples sintered at 1600 °C for Y and Gd-doped CeO 2. The unique temperature dependence of fracture strength on doped CeO2 is observed. It shows the local minimal value at around 600 °C and the fracture strength increases with increasing temperature. The fracture surface structure drastically changes with changing temperature observed by SEM. Since we observed the close coincidence between the fracture strength and the ratio of transcrystalline fracture surface for all samples, it is concluded that the increase of fracture strength at high temperature in doped CeO2 can be attributed to the temperature dependence of transcrystalline fracture strength. Typical creep curves of 2, 5, 10 and 20 YDC were measured under constant load in air. The creep rate decreases with increasing the dopant concentration. From the analysis of creep properties, the creep is controlled by cerium vacancy diffusion and change of ceria vacancy concentration decreases creep rate.

Original languageEnglish
Title of host publicationProceedings of the 6th International Conference on Fuel Cell Science, Engineering, and Technology
Pages85-91
Number of pages7
DOIs
Publication statusPublished - 2008 Dec 1
Event6th International Conference on Fuel Cell Science, Engineering, and Technology - Denver, CO, United States
Duration: 2008 Jun 162008 Jun 18

Publication series

NameProceedings of the 6th International Conference on Fuel Cell Science, Engineering, and Technology

Other

Other6th International Conference on Fuel Cell Science, Engineering, and Technology
CountryUnited States
CityDenver, CO
Period08/6/1608/6/18

ASJC Scopus subject areas

  • Energy Engineering and Power Technology
  • Fuel Technology

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