Reactivity in LaGaO3/Ni and CeO2/Ni Systems

✍ Scribed by N. Solak; M. Zinkevich; F. Aldinger

• Publisher: John Wiley and Sons
• Year: 2006
• Tongue: English
• Weight: 386 KB
• Volume: 6
• Category: Article
• ISSN: 1615-6846
• DOI: 10.1002/fuce.200500106

✦ Synopsis

Abstract

The reactivity in CeO~2~/Ni and LaGaO~3~/Ni systems, which are constituents of intermediate temperature solid oxide fuel cell (IT‐SOFC) anodes, has been investigated both computationally and experimentally. The CALPHAD‐method (CALculating of PHAse Diagrams), employing BINGSS and THERMOCALC software, was used to obtain a self‐consistent set of Gibbs energy functions describing the systems. Interactions in the LaGaO~3~/Ni system were predicted using a thermodynamic database developed for the La‐Ga‐Ni‐O system. Similarly, to analyze the CeO~2~/Ni system, the Ce‐Ni‐O ternary phase diagram was calculated using known thermodynamic data for binary Ce‐O, Ni‐O, and Ce‐Ni systems. The experimental work was designed based on the calculated phase diagrams. While the La‐Ga‐Ni‐O system experiments were conducted in air, the Ce‐Ni‐O system was also investigated in a reducing atmosphere. The calculated Ce‐Ni‐O diagram is in good agreement with the experimental results. It has been found that NiO does not react with CeO~2~. Extended solid solutions of La(Ga,Ni)O~3~, La~2~(Ni,Ga)O~4~, and La~4~(Ni,Ga)~3~O~10~ were found in the La‐Ga‐Ni‐O system. Additionally, the compound LaNiGa~11~O~19~, with magnetoplumbite‐type structure, has been found, which has not been reported in the literature so far. It is concluded that La~2~NiO~4~ is not chemically compatible, as a cathode material, with the LSGM electrolyte.