Sinterability, microstructures and electrical properties of Ni/Gd-doped ceria cermets used as anode materials for SOFCs
✍ Scribed by V. Gil; C. Moure; J. Tartaj
- Publisher
- Elsevier Science
- Year
- 2007
- Tongue
- English
- Weight
- 652 KB
- Volume
- 27
- Category
- Article
- ISSN
- 0955-2219
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✦ Synopsis
The influence of Ni content in Ni-CGO cermets on their electrical conductivity was investigated in order to create the most suitable microstructure. Ni-CGO (50/50, 45/55 and 40/60 wt%) powder mixtures were prepared by the polymeric organic complex solution method using ethyleneglycol as a polymerized soluble alcohol in water. By heat treatment a composite of ultrafine nickel oxide homogeneously dispersed in the CGO ceramic matrix was attained. After sintering of NiO-CGO composites in air at 1350 • C for several times and reducing treatment in N 2 90%-H 2 10% atmosphere, the microstructures showed a uniform distribution of porous metallic Ni particles surrounded by microporous spaces with total porosity (closed and opened) of ≈20-25%. The electrical properties of Ni-CGO cermets sintered at 1350 • C for 2 h were studied using impedance spectroscopy in the temperature range from 500 to about 700 • C in argon atmosphere. The Ni-CGO cermets showed metallic behaviour over all the range at temperatures studied, indicating a uniform and fine-grained microstructure in which the Ni-Ni particle contacts were predominant.