Mechanical behavior and electrical conductivity of La1-xCaxCoO3 (x=0, 0.2, 0.4, 0.55) perovskites

    Authors

    S. Pathak; J. Kuebler; A. Payzant;N. Orlovskaya

    Comments

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    Abbreviated Journal Title

    J. Power Sources

    Keywords

    Perovskite; Modulus; Bending strength; Fracture toughness; Ferroelasticity; Conductivity; LANTHANUM-GALLATE ELECTROLYTE; OXIDE FUEL-CELLS; SPIN-STATE; LACOO3-BASED CERAMICS; MAGNETIC-PROPERTIES; ELASTIC PROPERTIES; CRYSTAL-STRUCTURE; TRANSITION; LA1-XSRXCOO3; TRANSPORT; Electrochemistry; Energy & Fuels

    Abstract

    This paper compares the important mechanical properties and the electrical conductivities from room temperature to 800 degrees C of four LaCoO3 based cobaltite compositions with 0, 20, 40 and 55% Ca2+ ions substituted on the A site of the perovskite structure respectively. Ca2+ doped lanthanum cobaltite materials are strong candidates for use as cathodes in lower temperature solid oxide fuel cells operating at or below 800 degrees C. Among these four cobaltite compositions, two (LaCoO3 and La0.8Ca0.2CoO3) were found to be phase pure materials, whereas the remaining two compositions (La0.6Ca0.4CoO3 and La0.45Ca0.55CoO3\) contained precipitation of secondary phases such as CaO and Co3O4. The mechanical properties of the four compositions, in terms of Young's modulus, four-point bending strength and fracture toughness measurements were measured at both room temperature and 800 degrees C. At room temperature, doping with Ca2+ was found to substantially increase the mechanical properties of the cobaltites, whereas at 800 degrees C the pure LaCoO3 composition exhibited higher modulus and strength values than La0.8Ca0.2CoO3. All of the four compositions exhibited ferroelastic behavior, as shown by the hysteresis loops generated during uniaxial load-unload compression tests. Electrical conductivity measurements showed the La0.8Ca0.2CoO3 composition to have the highest conductivity among the four compositions. (C) 2009 Elsevier B.V. All rights reserved.

    Journal Title

    Journal of Power Sources

    Volume

    195

    Issue/Number

    11

    Publication Date

    1-1-2010

    Document Type

    Article

    Language

    English

    First Page

    3612

    Last Page

    3620

    WOS Identifier

    WOS:000275386100035

    ISSN

    0378-7753

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