  Proton-conducting oxides have potential applications in hydrogen sensors,
hydrogen pumps, and other electrochemical devices including the tritium
purification and recovery systems of nuclear fusion reactors. Although the
distribution of hydrogen (H) in such oxide materials is an important aspect,
its precise measurement is difficult. In the present study, the hydrogen
solubility and diffusivity behavior of BaZr0.9Y0.1O2.95 (BZY),
BaZr0.955Y0.03Co0.015O2.97 (BZYC), and CaZr0.9In0.1O2.95 (CZI) were studied
using tritiated heavy water vapor i.e., DTO (~2 kPa, tritium (T) = 0.1%) by
converting the photostimulated luminescence (PSL) values of the imaging plate
(IP). The samples were exposed to DTO vapor at 673 K for 2 h or at 873 K for 1
h. The disc-shaped oxide specimens (diameter ~7.5 mm; thickness ~2.3 mm;
theoretical density (TD) > 98 %) were prepared by conventional powder
metallurgy. The IP images of the specimen surfaces of all the three materials
T-exposed revealed that BZY showed the most uniform T distribution with the
highest tritium activity. The cross-sectional T concentration profiles of the
cut specimens showed that T diffused deeper into BZY and BZYC than into CZI.
The hydrogen solubility and diffusivity in the CZI specimen were lower than
that in the BZY and BZYC specimens. This suggested that barium zirconates were
more favorable proton conductors than calcium zirconates.
