Stability and oxygen transport properties of Pr2NiO4+δ ceramics

✍ Scribed by A.V. Kovalevsky; V.V. Kharton; A.A. Yaremchenko; Y.V. Pivak; E.N. Naumovich; J.R. Frade

• Publisher: Elsevier Science
• Year: 2007
• Tongue: English
• Weight: 406 KB
• Volume: 27
• Category: Article
• ISSN: 0955-2219
• DOI: 10.1016/j.jeurceramsoc.2007.02.136

✦ Synopsis

The oxygen permeability and stability of dense Pr 2 NiO 4+δ ceramics have been appraised in comparison with K 2 NiF 4 -type lanthanum nickelate. In oxidizing atmospheres, Pr 2 NiO 4+δ exhibit an extensive oxygen uptake and decomposition into the Ruddlesden-Popper-type Pr 4 Ni 3 O 10 and praseodymium oxide at temperatures below 900 • C. At 900-950 • C when the K 2 NiF 4 -type praseodymium nickelate is stable in the ceramic membranes placed under an oxygen partial pressure gradient, the steady-state oxygen permeability of Pr 2 NiO 4+δ is similar to La 2 NiO 4+δ . 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 Pr 2 NiO 4+δ in reducing atmospheres, estimated from the p(O 2 ) dependencies of total conductivity and Seebeck coefficient, is lower than that of La 2 NiO 4+δ , probably due to a smaller size of the A-site cation.