An ERDA study on proton migration induced by electric potential in SrZrO_3, SrCeO_3, and BaCeO_3 oxides: measurements of proton transport number and proton diffusivity

摘要

Migration of protons dissolved in acceptor doped SrZrO_3, SrCeO_3 and BaCeO_3 oxides has been examined under an applied electric potential over a range of temperature from 25 to 220 deg. Protons which dissolved in these oxides migrated to the cathode, and they were trapped there when the cathode material had a good ability to getter the migrating hydrogen. The amount of hydrogen accumulated in the cathode could be measured by the ERDA method using a high-energy ~4He beam. We measured the amount of hydrogen in the cathode while monitoring the dc current passed through the oxide specimen. The proton transport number was determined from the ratio of the number of hydrogen in the cathode to the total numbers of charge through the specimen. The diffusion coefficient of proton was evaluated using the proton transport number and proton concentration in the specimen.