Papers by Keyword: Ceramic Oxides

Abstract: In this paper, the phenomenon of steady-state cation demixing in yttria-stabilized zirconia in an electric field is examined for the case of an open system wherein the defects are everywhere close to internal surfaces which allow the Schottky-defect reaction to occur (very fine grain material). The effect of the constant electric field assumption as a substitute for the constant current condition is analyzed for diffusion by vacancy-pairs and by vacancy-triplets over a wide range of applied electric fields. It is shown that the assumption of a constant electric field provides only a moderate correction to the shape of the demixing concentration profile.

Abstract: Electrical charges may be transported in ceramics by not only electrons but also by electron-holes, ions, and protons. Especially in nuclear fusion environments, electrical conductivity by proton migration (protonic conduction) will play an important role, as supply of hydrogen isotopes is sufficient and working temperature for ceramics will be in general high. In the present paper, radiation effects on the electrical conductivity of perovskite-type oxides will be reviewed, emphasizing radiation effects on transport behaviors of hydrogen and on reducing behaviors of oxide ceramics. Some perovskite-type oxides are known to have large protonic conductivity and an electrical charge state of some atomic elements composing them can be studied easily by spectroscopic techniques.