Variation of mechanical properties of YSZ upon cubic to tetragonal phase transformation promoted by impurity Ni

H. Umemura, C. Sekizawa, S. Watanabe, K. Yashiro, T. Kawada

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

Abstract

In fabrication of an SOFC, dissolution of a small amount of NiO into YSZ electrolyte is often observed. With expectation of changing mechanical properties under similar conditions, measurements were carried out with the samples treated before and after annealing in reducing atmospheres. Elastic moduli were measured by a resonance method, and fracture strength was evaluated by a small punch technique. Some of the sample pieces were annealed with flowing 1%H2-1.2%H2O mixed gas at 900℃ for 15 h, 50 h, and 170 h. Raman scattering spectroscopy revealed that the phase of the annealed samples showed gradual transition from cubic to tetragonal. Young's modulus and fracture stress of the as-sintered sample showed minimum at a temperature around 400 to 500℃ where large internal friction was observed. This suggests that the mechanical properties were determined not by the concentration of Y2O3 but by the crystal structure that mainly appeared in the sample.

Original languageEnglish
Title of host publicationSolid Oxide Fuel Cells 16, SOFC 2019
EditorsK. Eguchi, S. C. Singhal
PublisherElectrochemical Society Inc.
Pages837-845
Number of pages9
Edition1
ISBN (Electronic)9781607688747
DOIs
Publication statusPublished - 2019 Jan 1
Event16th International Symposium on Solid Oxide Fuel Cells, SOFC 2019 - Kyoto, Japan
Duration: 2019 Sep 82019 Sep 13

Publication series

NameECS Transactions
Number1
Volume91
ISSN (Print)1938-6737
ISSN (Electronic)1938-5862

Conference

Conference16th International Symposium on Solid Oxide Fuel Cells, SOFC 2019
CountryJapan
CityKyoto
Period19/9/819/9/13

ASJC Scopus subject areas

  • Engineering(all)

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