Microstructural evolution in cerium dioxide irradiated with heavy ions at high temperature

Cerium dioxide (CeO₂) is a well-studied oxide because of its technological applications, such as a major component in the catalysts, stable capacitors and so on. CeO₂ with a cubic fluorite structure is also expected as the material for simulating behaviors of uranium dioxide under energetic particle irradiation, which leads high burn-up structure attributable to pressure increase in fuel cladding tubes. In this work, the stability of crystal structure and surface morphology change in CeO₂ will be clarified. Polycrystalline samples were irradiated with 300 keV Xe⁺, 18 MeV I⁵⁺, 350 keV O⁺ and 12 MeV O³⁺ ions at temperatures from 370 to 1000 K. Microstructural evolutions was investigated with Scanning electron microscopy, Raman Spectroscopy and X-ray diffractometry. Irradiation effects at high temperature were observed as surface etching and resulting bubble formation, however blistering was not detected. Raman spectra and diffraction data indicates diffusion of oxygen vacancies is sufficient at 900 K and above.