Effect of different electrode materials on electrophoretic depositional behavior of yttria-stabilized zirconia powder

Abstract

The electrophoretic depositional (EPD) behavior of yttria-stabilized zirconia (YSZ) powder with 8 mol% Y2O3, which is a common material for oxygen sensors as a solid electrolyte, was investigated on stainless steel and carbon based substrates. Ethanol + HNO3 based suspensions were used for the EPD experiments, and three different YSZ powders, one commercially available powder and two own-made coprecipitated powders, were deposited. The latter powders were calcined at 900 and 1200 °C, respectively. The concentration of the suspension was 3 g/300 cm3 and a small amount of HNO3 solution was added as a dispersant. A DC electric field of 100–200 V/15 mm was applied between parallel electrodes. On stainless steel electrodes it was found that the own-made coprecipitated powder calcined at 1200 °C, showing the best deposition properties, whereas the commercial YSZ powder showed the best depositional properties on carbon electrodes. These characteristic depositional behaviors are discussed with regard to the adhesive force between the particles and the different electrodes, and some powder properties, e.g., particle size distribution and packing behavior. A thick, continuous, free-standing YSZ film with a thickness of around 10 μm was successfully obtained after firing the deposit on the carbon electrode in flowing air.