Evaluation of the hydrogen solubility and diffusivity in proton-conducting oxides by converting the PSL values of a tritium imaging plate

• Main Authors: M. Khalid Hossain, Kenichi Hashizume, Yuji Hatano
• Format: Article
• Language: English
• Published: Elsevier 2020-12-01
• Series: Nuclear Materials and Energy
• Subjects: Barium zirconate (BaZrO3); Calcium zirconate (CaZrO3); Photostimulated luminescence (PSL); Tritium imaging plate (TIP); Hydrogen solubility and diffusivity; Fusion reactors materials
• Online Access: http://www.sciencedirect.com/science/article/pii/S2352179120301411

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) greater than 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.