Microstructures and mechanical properties of Ce1−xCaxO2−y (x = 0.05, 0.1, 0.2) with different sintering temperatures

In this study, the microstructures and mechanical properties of Ca-doped CeO2 affected by different sintering temperatures and various dopant concentrations have been systematically investigated. Transmission electron microscopy (TEM) and X-ray diffraction (XRD) revealed that a seemingly individual Ca-doped CeO2 system may consist of multiple types of doped CeO2 phases. X-ray photoelectron spectroscopy (XPS) analysis demonstrated that the chemical state of the Ce element is less dependent on the sintering temperature, while increasing the sintering temperature may cause segregation of the Ca elements to form CaO phase. Nanoindentation tests showed that Ca-doped CeO2 has better fracture toughness compared to rare-earth (RE) doped CeO2; the relationship between the sintering temperature and the mechanical property has been discussed.