for sample sintered at 1000 °𝐶 and 1650 °𝐶, respectively, where they differentiate by ~30%. The higher radial shrinkage of the samples was attributed to the pressure distribution under uniaxial press. Theoretically, a gaussian pressure distribution is generated under almost every uniaxial press. Therefore, always a stress gradient is produced inside the die press from the center to the pellet's rim. Samples sintered at 1000 °𝐶, 1100 °𝐶, and 1200 °𝐶 exhibited higher 𝑅: 𝐴 ratio (although smaller individual 𝐴% and 𝑅%) while the samples sintered at higher temperatures showed a barely perceptible positive slope where 𝑅: 𝐴 ratio ~1.2. At this point, one can assume that 1200 °𝐶 could be consider as the temperature, sufficiently high that grain growth kinetic rate is fast enough /activated to eliminate open pores to the surface and make the pellet heterotic. including samples sintered at high temperatures showed some residual porosities. These trapped pores were mostly observed at the 3and 4-grain-boundaries junctions which specifically were responsible for stopping the densification process and reaching the plateau. However, samples sintered in low-temperature regime, showed very low density, with open pores compared to other ceramic oxides such as YSZ. This effect is more tangle when the low density of the samples sintered at 1000 °𝐶 to 1200 °𝐶 is concerned where the process was controlled by sluggish diffusion of cations at lower temperatures. Politova et al. discussed that the 𝑆𝑐 ! 𝑂 " -𝑍𝑟𝑂 ! system is prone to lower achievable density. This phenomenon occurs owing to the slower rate of cation diffusion in this system compared to that of anion transport. However, addition of 𝐶𝑒 "%,&% enhanced the mobility by isomorphous substitution of the host lattice, 𝑍𝑟𝑂 ! . The enhancement of conductivity was attributed to the lattice parameter changes in the host unit cell where larger cation 𝐶𝑒 &% (𝑟 -. "# = 0.97 Å) randomly substitute 𝑍𝑟 &% (𝑟 () "# = 0.84 Å) sites at the eight folded coordination (8𝐶𝑁) . The powder particles have a solid-vapor surface energy (𝐽. 𝑚 5! ). The energy per unit mass can be stored as excess surface area (𝐽. 𝑘𝑔 51 ). However it is not thermodynamically possible to consume all the excess surface energy during the sintering, therefore the emergence of the other interfaces add energy to the system such as grain boundaries that cause the densification plateau and the higher relative density couldn't be achieved . Figure shows the effect of the sintering temperature on the density, grain size, and pore size of the as-sintered pellets. The density graph shows a sigmoidal dependence of the density on sintering temperature with a reached plateau around 1500 °𝐶, indicating the saturation limit of the densification process. The densification plateau occurrence depends on several factors such as particle size distribution of the powder particle packing, sintering heating rate (here 2 °𝐶. 𝑚𝑖𝑛 51 ), and the sintering atmosphere (air) .