Vertical sintering to measure the uniaxial viscosity of thin ceramic layers

A novel method is proposed for the determination of the uniaxial viscosity of porous ceramic layers upon sintering. This approach is based on the application of a continuous but very low tensile stress to the densifying powder compact whose deformation is continuously monitored by an optical system. The viscosity of the system can be determined as a function of temperature and density from the sintering rate differences measured between loaded and unloaded samples. The uniaxial viscosity of porous Y2O3 doped ZrO2 (YSZ) and NiO-YSZ composites was measured using the proposed approach. The results were used to predict the curvature evolution of bilayers used in solid oxide fuel cell applications, obtaining a fairly good agreement between the model and the data recorded experimentally.