Study of the Electrical Conductivity of Plasma-Sprayed 4.5mol% Yttria Stabilized Zirconia Coatings

Abstract

Abstract Y2O3 stabilized ZrO2 (YSZ) coating is widely applied to the electrolyte layer in solid oxide fuel cell. With regard to the application of YSZ coating to solid oxide fuel cell, the electrical conductivity of YSZ coating is of essential importance. In this study, YSZ coating was deposited by plasma spraying using a sinter-crushed powders containing 4.5mol% Y2O3. The electrical conductivity of the coating at both directions parallel and perpendicular to the coating surfaces was measured by a direct current approach. The measurement was carried out at a temperature range from 600 °C to 1000 °C. The effect of spray distance on the electrical conductivity was also examined. The test showed that 4.5YSZ layer yielded the electrical conductivities of 2.2 s·m-1 and 4.3 s·m-1 at a temperature of 1000 °C in both direction perpendicular and parallel to the coating surface, respectively. It is clear that the electrical conductivity of the coating was lower than the identical sintered bulk material. The electrical conductivity of YSZ coatings in this study was of one-fifth to one-fourth in perpendicular direction and about one-half in parallel direction compared with the sintered YSZ bulk. It was considered that the lower electrical conductivity of the coating compared with the identical sintered bulk results from the lamellar structure with the limited interface bonding.