Tetragonal phase stability maps of ceria-yttria co-doped zirconia: From powders to sintered ceramics

Abstract

Ceria-Yttria co-doped tetragonal zirconia is an attractive class of materials having high strength, toughness and thermal stability. In this study, several co-doped zirconia powders with different stabilizers contents were synthesized via continuous hydrothermal flow synthesis (CHFS). The CHFS was concluded as a suitable method in synthesizing ultrafine tetragonal zirconia particles with controlled morphology. The synthesized powders as well as some commercial powders were heat-treated both in the form of powders and pellets between 1150 and 1500°C and their crystalline structure after cooling to room temperature was studied. The results were used to map out the stability range of the tetragonal phase. The developed diagrams are useful tools to select the appropriate amounts of stabilizers applicable for different sintering temperatures and for samples with different target densities.

Solvothermal Synthesis Routes to Substituted Cerium Dioxide Materials

“…Materials in the CeO 2 -Y 2 O 3 -ZrO 2 system have been prepared under solvothermal conditions. Wang et al found that the activation energy of crystal growth is significantly dependent on the CeO 2 concentration [171], and continuous flow synthesis (410 • C, 27 MPa) has been used to form ultrafine stabilised tetragonal zirconia particles [172], while a wide range of nanoscale crystal forms, with intricate morphologies, were possible by inclusion of surfactants, Figure 20 [173]. In the even more complex system ceria-zirconia-yttria-lanthana, high-surface area nanostructured materials have been formed with the aid of lauric acid and dodecylamine [174].…”

“…Inorganics 2021, 9, x FOR PEER REVIEW 24 of 35 flow synthesis (410 °C, 27 MPa) has been used to form ultrafine stabilised tetragonal zirconia particles [172], while a wide range of nanoscale crystal forms, with intricate morphologies, were possible by inclusion of surfactants, Figure 20 [173]. In the even more complex system ceria-zirconia-yttria-lanthana, high-surface area nanostructured materials have been formed with the aid of lauric acid and dodecylamine [174].…”

Improving the fracture toughness of stabilized zirconia-based solid oxide cells fuel electrode supports: Effects of type and concentration of stabilizer(s)

“…In a previous study [30] we developed transformation boundary diagrams for Ce-Y co-doped zirconia, applicable for different temperatures and degrees of powder packing. With this, it is possible to choose the optimum amount of stabilizing agents such that the tetragonal phase has enough stability; yet not being over-stabilized.…”

“…With this, it is possible to choose the optimum amount of stabilizing agents such that the tetragonal phase has enough stability; yet not being over-stabilized. It should be noted that the sintering temperature and density of the tetragonal zirconia ceramic are important parameters affecting the stability of the tetragonal phase, and should be considered when choosing the stabilizer concentration [30][31][32].…”

“…In this study, six zirconia compounds with different stabilizer contents (Table 1) were used as the stabilized zirconia phase in the SOCs fuel electrode supports. Four compounds were identified by said previous study [30]. The fracture toughness values of the supports manufactured using these four compounds were compared to the state-of-the-art material, 3YSZ (denoted in this paper as 5.8YO1.5-SZ) and the widely used 8YSZ (denoted as 14.8YO1.5-SZ) based supports.…”