Preparation of an yttria-stabilized zirconia electrolyte on a porous Ni-based cermet substrate by laser chemical vapor deposition

Abstract

This work investigated the use of laser chemical vapor deposition (LCVD) to apply an yttria-stabilized zirconia (YSZ) thin film electrolyte to a porous Ni metal/YSZ substrate. Using this process, a dense YSZ film having a columnar structure and small grain sizes was successfully fabricated on a porous cermet substrate at a relatively low temperature of approximately 700 °C. A 15 µm thick film was obtained following a deposition time of only 20 min. Solid oxide fuel cell (SOFC) power generation tests were performed using the sample on which YSZ was deposited and stable power generation was observed. However, the open circuit voltages were lower than the theoretical values and the ohmic loss of the specimen was significantly higher than that estimated from the conductivity of YSZ. These inferior performance parameters can possibly be attributed to the formation of cracks in the electrolyte film during the SOFC test, and thus enhanced performance could be obtained by suppressing crack formation. In addition, the reason for the crack formation was also discussed in this work.