Optimal Control of the Sintering Strain Rate of Yttria-Stabilized Zirconia Electrolytes for Solid Oxide Fuel Cells Using a Thermal−Mechanical Analyzer during the Sintering Process

The optimal sintering trajectories of three-dimensional (3D) yttria-stabilized zirconia (YSZ) tapes were prepared using a dynamic optimization method under the controlled sintering strain. The sintering process model was carried out by the combination of both the heat transport equation and the dynamic equation of the sintering strain rate, constructed by thermal−mechanical analyzer (TMA) data. The heating pathway of a constrained strain rate case was determined numerically and was further experimentally carried out by the TMA test. Results show that the distribution of the strain rate in the ceramic tape was influenced by the sample size and heating conditions. The optimally sintered YSZ electrolyte showed better electronic performance than those with constant heating rates based on the conductivity tests. Therefore, the formation of the strain rate can be one of the factors that influenced the quality of the YSZ electrolyte in the sintering process.