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Electrical Properties, Cation Distributions, and Thermal Expansion of Manganese Cobalt Chromite Spinel Oxides
Author(s) -
Liu Yingjia,
Fergus Jeffrey W.,
Cruz Clarina Dela
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.12254
Subject(s) - spinel , chromia , materials science , cobalt , chromium , chromite , manganese , solid oxide fuel cell , oxide , thermal expansion , alloy , inorganic chemistry , chemical engineering , metallurgy , chemistry , electrode , anode , engineering
As the oxidation and chromium volatilization of chromia‐forming alloy interconnects can cause Solid oxide fuel cells ( SOFC ) cathode poisoning and cell degradation, spinel coatings like Mn 1.5 Co 1.5 O 4 have been applied as a barrier to oxygen and chromium diffusion. To evaluate their long‐term stability, the properties of the reaction layer between the Mn 1.5 Co 1.5 O 4 coating and Cr 2 O 3 scale formed on the alloy surface need to be characterized. Therefore, compositions of Mn 1.5−0.5 x Co 1.5−0.5 x Cr x O 4 ( x = 0–2) were prepared to investigate their electrical properties, cation distributions, and thermal expansion behavior at high temperature. With increasing Cr content in manganese cobalt spinel oxides, the cubic crystal structure is stabilized and the electrical conductivity and coefficient of thermal expansion both decrease. The cation distributions determined from neutron diffraction show that Cr and Mn have stronger preference for octahedral sites in the spinel structure as compared with Co .