Phase Transformation Behavior, Mechanical Properties Under Thermal Stress, and Slag-Induced Erosion of 2-4 mol% CeO-Doped CaO-Stabilized Zirconia.

We investigated the phase transitions, mechanical properties, and chemical durability of a composition of 9 mol% CaO-stabilized zirconia (9CSZ) doped with 2-4 mol% CeO under thermal stress against molten slag. The monoclinic phase fraction of 9CSZ was 7.14% at room temperature, and CSZ doped with 2-4 mol% CeO showed a slightly lower value of 5.55-3.72%, with only a minor difference between them. The microstructure of 9CSZ doped with 2-3 mol% CeO was similar to that of undoped 9CSZ, whereas the microstructure of 9CSZ doped with 4 mol% CeO exhibited noticeable grain refinement. The mechanical properties of CSZ at room temperature tended to improve as the CeO doping concentration increased. The Vickers hardness increased from 1088.4 HV to 1497.6 HV when the CeO doping amount was 4 mol%, and the specific wear amount decreased from 1.5941 to 1.1320 × 10 mm/Nm. This tendency remained similar even after applying thermal stress. The monoclinic phase fraction of 9CSZ increased from 7.14% to 67.71% after the erosion experiment with the CaF₂-based slag. CeO-doped CSZ had a lower monoclinic phase fraction than CSZ after the erosion experiment, but as CeO content increased from 2 to 4 mol%, the fraction rose to 4.07%, 30.85%, and 77.11%.