Dependence of Size of YSZ Nanoparticles in Electrophoretic Deposition on Conducting Method on the Surface of NiO-YSZ Composite for SOFCs

In present work, three different methods were used for conducting the anodes. First, a thin layer of graphite was coated on the surface of NiO-YSZ composites by painting. In the second method, NiO-YSZ composites were reduced at 850 °C in hydrogen/argon atmosphere and the Ni YSZ cermets were produced. In the third method, although no methods were used for electrical conducting, only substrates with more than 50% open porosity could use. A uniform and stable YSZ suspension was applied for electrophoretic deposition in mixed acetone-ethanol medium. Afterwards, sintering was done at high temperature. Then, the current of circuit was recorded and weight of deposition and film density were calculated. Finally, microstructure of coating and its thickness were observed by SEM for green and sintered samples. By increasing electrical resistivity of the substrate, the current of circuit, weight of deposition and film density reduced. It was also detected that the size of deposited particles decreased less than 100 nm by decreasing electrical conductivity. The smallest particle size that was achieved by using the saturated substrate was 59 nm. By using substrates with high electrical conductivity, the quality of the deposited film was improved.