CHARACTERIZATION OF THE ZRCO-HYDROGEN SYSTEM IN VIEW OF ITS USE FOR TRITIUM STORAGE

To evaluate ZrCo as a getter material for the storage of tritium, a study on as-received and activated ZrCo as well as on ZrCoHx was carried out employing surface analytical methods such as XPS, AES, and electron microprobe. Complementary information on the bulk of the various species was obtained from X-ray diffraction. Loading ZrCo with hydrogen () at room temperature yielded ZrCoHx with x = 2.91 ± 0.04. Pressure-composition loading and deloading isotherms for the systems ZrCo/H2 and ZrCo/D2 were determinated at temperatures below 300 °C. The hysteresis factor was quantified. The average enthalpy change and entropy change for the absorption of hydrogen (or deuterium) were found to be −81.5 ± 1.6 kJ/mol (−87.5 ± 0.8 kJ/mol) and −132.7 ± 2.7 J/mol•K (−146.4 ± 2.3 J/mol•K) respectively for the plateau region (0.8 < x < 2.0). Temperature cycling under isopleth conditions caused a small trapping that is restricted to the plateau region. © 1990, American Chemical Society. All rights reserved.