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

Abstract

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.

Effect of Stone Coal Chemical Composition on Sintering Behavior during Roasting

“…During the roasting of stone coal, with increasing roasting temperature, volume shrinkage occurs and the apparent density of roasted sample increases. 18 When the temperature arrives at a certain value, the apparent density of roasted sample begins to increase significantly, and this temperature is regarded as the SBT. In the experiment, the apparent density of roasted samples, plotted as a function of roasting temperature with different CaO addition content, is provided in Figure 1.…”

Thermal Barrier Coatings Overview: Design, Manufacturing, and Applications in High-Temperature Industries

“…The SEM images disclosed that the porosity of the ceramic material was abridged with the rise in temperature. The YSZ particles become closer creating more compact structures, and the material became denser with the surge of temperature …”

“…Scanning electron microscopy (SEM) micrographs of YSZ at (a) 300, (b) 1073, (c) 1473, and (d) 1773 K. Reprinted with permission from ref , Copyright 2009, American Chemical Society.…”

“…Effective thermal barrier materials should demonstrate such properties as low thermal diffusivity, phase stability and thermal shock resistance during thermal cycling, strong adherence to the substrate, and shielding against oxidation and corrosion for both the metallic bond coat and the substrate. 16 In general, titania, zirconia, alumina, porcelain, porcelainite, pyrochlores (A 2 3+ B 2 4+ O 7 ), garnets (Y 3 Al x Fe 5 -xO 12 ), monazite (LaPO 4 ), perovskites (ABO 3 ), lanthanum magnesium hexa-aluminate (LaMgA l1 O 19 ), and even diamond have all been measured to have low thermal diffusivity and can therefore be considered as potential TBC materials. 17 Yttria partially stabilized zirconia (YTZP) is a ceramic material seen in a wide-range of applications, owing to its exceptional overall properties (e.g., relatively low thermal conductivity, high dielectric constant, excessive fracture toughness, and chemical inertness at high temperatures).…”

“…The YSZ particles become closer creating more compact structures, and the material became denser with the surge of temperature. 19 Other ceramic topcoat layers such as zirconates have been the subject of ongoing academic investigation. Pyrochlore La 2 Zr 2 O 7 was found to be a potential alternative to YSZ thanks to its lower Young's modulus, comparable fracture toughness, and ∼20% lower thermal conductivity at elevated temperatures.…”