Optimal heating trajectories of controlling green tapes of YSZ electrolyte deformation using TMA during thermal processing

The optimal heating trajectories to minimize the time required for the organic additives removal in yttria-stabilized zirconia (YSZ) green tapes were determined using a dynamic optimization method. The removal process model was described by the mass transport of the volatile gas evolved from the thermal decomposition of the organic additives inside the tapes and the kinetics of the decomposition. The pressure buildup of the sample tapes formed by the volatile gas can be estimated by a numerical simulation method; meanwhile, the deformation (strain) of the tape caused by the pressure buildup was measured by a thermal mechanical analyzer (TMA) during the thermal processing. Results show that the formation of the maximum pressure buildup at the center of the cubic tape is influenced by the sample size and heating conditions. In addition, the dynamic strain at the center of the sample measured by TMA agrees with the formation of the pressure buildup estimated by the numerical calculation. Moreover, the optimal heating trajectories determined by the dynamic optimization scheme with the constraint of the formation of the maximum pressure buildup were verified from the tape deformation analysis by the TMA tests.