Effects of ionization on migration of hydrogen doped into BaCe 0.9Y 0.1O 3 − δ

Abstract

The effects of radiation on the electrical and proton conductivities of hydrogen (H)-doped BaCe 0.9Y 0.1O 3 − δ were studied by performing irradiation using 1.8-MeV electron beams at ionization dose rates of either 10 or 1000 Gy/s. The base conductivity ( σ BC) of BaCe 0.9Y 0.1O 3 − δ became higher under electron irradiation that is indicative of radiation-induced conductivity (RIC; σ RIC). The difference between RIC and the base conductivity, ΔRIC ( σ RIC − σ BC), at an ionization dose rate of 10 Gy/s increased as the irradiation temperature increased from 298 to 623 K. It was found that the ΔRIC value for H-doped BaCe 0.9Y 0.1O 3 − δ only at 10 Gy/s and 473 K was approximately one order of magnitude higher than that of nondoped BaCe 0.9Y 0.1O 3 − δ . The results indicate that the radiation-induced conduction occurs not only due to electronic excitation but also due to hydrogen diffusion increased by the ionizing effects of radiation. The RIC, ΔRIC, and base conductivity of samples irradiated at 10 Gy/s and 623 K and at 1000 Gy/s and 473 K gradually reduced as the irradiation time increased; this is indicative of radiation-induced electrical degradation (RIED). The dependence of the conductivities on the irradiation time is not affected by the presence of doped hydrogen. Radiation-enhanced diffusion of the constituent oxygen not only leads to the occurrence of RIED but also suppresses the migration of protons activated by the ionizing effects of radiation.