Hideki Hamatani1, Hisashi Kumaoka2, Toshifumi Yahata2 and Toyonobu Yoshida3
1Graduate Student, The University of Tokyo, Tokyo. Present address: R & D Laboratories-II, Nippons Steel Corporation, Sagamihara
This study was aimed at developing integrated fabrication process for solid oxide cells (SOFC) with radio-frequency plasma spraying (RFPS) and/or hybrid plasma spraying (HYPS). Fundamental studies concerning particle velocity and deformation of ZrO2-12 wt%Y2O3 (YSZ) showed that even the lower particle velocities in RFPS (20 m/s) and HYPS (40-70 m/s) compared with the case in direct current plasma spraying (~200 m/s), were found to be sufficient for the deformation of impinging molten YSZ particles on the substrate. RFPS, however, imposed a severe limitation on the substrate position because it led to short flying distance of molten particles. In this respect, HYPS was considered to be superior than RFPS. Actually, using 75 μm YSZ powder, HYPS made it possible to get not only dense YSZ coating with the relative density higher than 98% but also good gas permeability lower than 5.7× 10-7 cm4/g•s (2500 mmH2O). Moreover, porous NiO and chemical stable LaCoO3 as electrodes could be prepared by Ar-O2 HYPS. Though the cell performance had not been investigated yet, these experimental results have proved that HYPS must be a strong candidate to open new aspects of the production process for SOFC, especially, from economical and engineering points of view.
radio-frequency plasma, hybrid plasma, plasma spraying, yttria stabilized zirconia, perovskite, solid oxide fuel cell
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