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Assessment of processing route on the performance of ceria‐based composites
Author(s) -
Grilo João P. F.,
Macedo Daniel A.,
Nascimento Rubens M.,
Marques Fernando M. B.
Publication year - 2021
Publication title -
international journal of energy research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.808
H-Index - 95
eISSN - 1099-114X
pISSN - 0363-907X
DOI - 10.1002/er.6438
Subject(s) - materials science , eutectic system , ceramic , composite material , ceramic matrix composite , conductivity , porosity , electrical resistivity and conductivity , phase (matter) , dielectric spectroscopy , molten salt , microstructure , electrode , metallurgy , chemistry , organic chemistry , electrochemistry , electrical engineering , engineering
Summary Gd‐doped ceria (GDC)‐based composites, including a eutectic mixture of lithium and sodium carbonate (NLC) as second phase, were prepared using several processing routes, namely chemical synthesis, co‐firing of both phases, or impregnation of a presintered porous matrix. LiAlO 2 ‐based composites were also prepared and used as reference. The structural, microstructural, and electrical properties (impedance spectroscopy in air, up to 700°C) of these materials were assessed in detail. A limited set of compositions was also used in measurements of total electrical conductivity at different oxygen partial pressures (from 0.21 to <10 −25 atm), in the 600°C to 700°C range. The results obtained confirmed the enormous impact of the processing route on the percolation of the ceramic phase. In the exploited range of operating conditions, GDC‐NLC composites prepared by infiltration of molten carbonates within a mechanically robust ceramic matrix exhibit a high total ionic conductivity strongly influenced by the contribution of the molten salt while the ceramic phase is decisive in the appearance of a significant component of electronic conductivity under reducing conditions.