Premium
Preparation, Structural Characterization, and Enhanced Electrical Conductivity of Pyrochlore‐type (Sm 1– x Eu x ) 2 Zr 2 O 7 Ceramics
Author(s) -
Xia X.L.,
Liu Z.G.,
Ouyang J.H.,
Zheng Y.
Publication year - 2012
Publication title -
fuel cells
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.485
H-Index - 69
eISSN - 1615-6854
pISSN - 1615-6846
DOI - 10.1002/fuce.201200015
Subject(s) - high resolution transmission electron microscopy , materials science , analytical chemistry (journal) , raman spectroscopy , pyrochlore , ceramic , electrical resistivity and conductivity , microstructure , conductivity , ionic conductivity , crystallography , transmission electron microscopy , chemistry , phase (matter) , nanotechnology , metallurgy , physics , organic chemistry , chromatography , electrode , electrolyte , optics , electrical engineering , engineering
(Sm 1– x Eu x ) 2 Zr 2 O 7 (0 ≤ x ≤ 1.0) samples are prepared by solid state reaction method using Sm 2 O 3 , Eu 2 O 3 , and ZrO 2 as starting materials. The phase composition and microstructure of (Sm 1– x Eu x ) 2 Zr 2 O 7 ceramics are investigated by X‐ray diffraction (XRD), scanning electron microscopy, high‐resolution transmission electron microscopy (HRTEM) coupled with selected area electron diffraction and Raman spectroscopy. XRD and TEM show that all the samples exhibit a single pyrochlore‐type structure. HRTEM observation indicates that the whole grain interior of Sm 2 Zr 2 O 7 ceramic is a perfect crystal free of any dislocation. Raman spectroscopy reveals that the degree of structural disorder of (Sm 1– x Eu x ) 2 Zr 2 O 7 ceramics increases gradually with increasing Eu content. The electrical conductivity of (Sm 1– x Eu x ) 2 Zr 2 O 7 ceramics is investigated by impedance spectroscopy in the air and hydrogen atmospheres, respectively. The electrical conductivity of (Sm 1– x Eu x ) 2 Zr 2 O 7 ceramics increases with increasing Eu content at identical temperature levels. Both the activation energy E g and the pre‐exponential factor σ 0g for the grain conductivity gradually increase with increasing Eu content. As the ionic conductivity shows no obvious change in both air and hydrogen atmospheres, the conduction of (Sm 1– x Eu x ) 2 Zr 2 O 7 is purely ionic with negligible electronic conduction.