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Oxygen Migration in Dense Spark Plasma Sintered Aluminum‐Doped Neodymium Silicate Apatite Electrolytes
Author(s) -
An Tao,
Baikie Tom,
Herrin Jason,
Brink Frank,
Felix Shin J.,
Slater Peter R.,
Li Sean,
White Tim J.
Publication year - 2013
Publication title -
journal of the american ceramic society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.9
H-Index - 196
eISSN - 1551-2916
pISSN - 0002-7820
DOI - 10.1111/jace.12489
Subject(s) - materials science , spark plasma sintering , conductivity , analytical chemistry (journal) , ionic conductivity , microstructure , crystallite , mineralogy , doping , grain boundary , neodymium , chemical engineering , electrolyte , metallurgy , chemistry , electrode , optoelectronics , chromatography , engineering , laser , physics , optics
Neodymium silicate apatites are promising intermediate temperature (500°C–700°C) electrolytes for solid oxide fuel cells. The introduction of Al promotes isotropic percolation of O 2− , and at low levels (0.83–2.0 wt% Al ) enhances bulk conductivity. To better understand the effect of Al ‐doping on intrinsic conductivity, and the impact of grain boundaries on the transport, dense Nd 9.33+ x /3 Al x Si 6− x O 26 (0 ≤ x ≤ 2) pellets were prepared by spark plasma sintering. Phase purity of the products was established by powder X‐ray diffraction and the microstructure examined by scanning electron microscopy. The ionic conductivity measured by AC impedance spectroscopy for the spark plasma sintered ceramics were compared with transport in single crystals of similar composition. Intermediate Al ‐doping (0.5 ≤ x ≤ 1.5) delivered superior overall conductivity for both the polycrystalline and single crystal specimens.