Oxygen Diffusion Phenomena and Hydrogen Incorporation in Reducing BaTiO_3 Ceramics Doped with Ho below Solubility Limit

摘要

Oxygen diffusion phenomena in BaTiO_3 ceramics doped with Ho of 5.2 × 10~(18)/cm~3 were studied in order to reveal the effect of reduction thermal annealing. The samples were reduced at 850 ℃ in a 3% H_2-Ar atmosphere before the oxygen diffusion experiments. The oxygen diffusion was carried out in the temperature range of 700-800 ℃. The measurement of diffusion profiles and ion images revealed the oxygen defect distribution caused by the annealing. The results show that the grain boundary acts as a layer blocking oxygen diffusion when the diffusion temperature is below the reduction temperature of 850 ℃.