The preparation of granular composite NiO-YSZ ceramic films, prepared by slurry spraying, demands rigorous control of processing variables, specially the slurry rheology due to its influence on the deposition process as well as on the film microstructure. This paper studied the influence of suspension formulation on both rheological behavior and microstructure of granular film. The following variables were chosen to prepare the suspensions: solid concentration, the NiO/YSZ mass proportion, NiO particle size, dispersant amount, kind of rheological changer, and mixture of solvents. The effect of these variables on the suspension rheology was analyzed considering the Mooney’s model for concentrated suspension. By using factorial fractional design it was possible to evaluate the formulation variables effects. It was determined that the defects present on the granular film are generated during the drying process and they happen due to wrong addictive choice.
Fractional Factorial design; viscosity; tixotropy; slurry formulation; microstructure
