スリップキャスト法による固体電解質型燃料電池用イットリア安定化ジルコニア (YSZ) 膜の製法

抄録

To fabricate the yttria-stablized zirconia (YSZ) films for solid oxide fuel cell by the slip casting, viscosity of YSZ slips and sintering property of green bodies have been investigated. Chlorine in as-received YSZ powders was removed as Cl^- ion by repetitive laundering of admixing distilled water. The sintering property of as-received YSZ powders was superior to that of laundered ones, because YSZ particles were condensed in the laundering process. Both as-received and laundered YSZ particles were stabilized in the slip with a deflocculant containing NH₄⁺ salt of polyacrylic acid as a major component. For some slips the square of thickness of casting layer, L², was proportional to the casting time, t. Casting rate consant, L²/t, was increased with increasing concentration of YSZ powders in the slips. The thickness of casting layer for fabricating YSZ films could be controlled by the casting data of YSZ slips. The relative densities of sintered YSZ specimens were 92 and 96% at sintering temperatures of 1300° and 1500°C, respectively. Dense YSZ films were fabricated by slip cast, and sintered without pressure at 1500°C. The I-V characteristics of the flat thick film type solid oxide fuel cell based on the YSZ electrolyte film of 140μm thick, La_0.6Sr_0.4MnO₃ cathode and NiO+YSZ anode was excellent, and the power of this cell was about 450mW/cm².