Stability and oxygen transport properties of Pr2NiO4+delta ceramics

resumo

The oxygen permeability and stability of dense Pr2NiO4+delta ceramics have been appraised in comparison with KNiF4-type lanthanum nickelate. In oxidizing atmospheres, Pr2NiO4+delta exhibit an extensive oxygen uptake and decomposition into the Ruddlesden-Popper-type Pr4Ni3O10 and praseodymium oxide at temperatures below 900 degrees C. At 900-950 degrees C when the K2NiF4-type praseodymium nickelate is stable in the ceramic membranes placed under an oxygen partial pressure gradient, the steady-state oxygen permeability of Pr2NiO4+delta is similar to La2NiO4+delta. The phase changes on cooling lead to considerably higher oxygen permeability, which becomes comparable to that of perovskite-type cobaltites, and to noticeable isothermal expansion. The stability of Pr2NiO4+delta in reducing atmospheres, estimated from the P(02) dependencies of total conductivity and Seebeck coefficient, is lower than that of LaNiO4+delta, probably due to a smaller size of the A-site cation. (c) 2007 Elsevier Ltd. All rights reserved.

palavras-chave

HIGH-TEMPERATURE; OXIDES; MEMBRANES; LA; CU

categoria

Materials Science

autores

Kovalevsky, AV; Kharton, VV; Yaremchenko, AA; Pivak, YV; Naumovich, EN; Frade, JR

nossos autores

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