Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
1627455 | Journal of Alloys and Compounds | 2006 | 8 Pages |
Annealed Pd exhibits supersaturation of the dilute phase before the hydride phase forms and this is characterized here by measurements of both |ΔHH| and equilibrium pH2pH2. Dilute phase |ΔHH| and pH2pH2 values were determined for annealed Pd for both absorption and desorption of H2 and the |ΔHH| were the same for both and the dilute phase H2 isotherms were also the same, i.e., absorption/desorption was reversible. Pd, which has a high dislocation density, however, does not exhibit supersaturation, and its |ΔHH| values are a continuous function of H/Pd in contrast to annealed Pd where there is a discontinuity at the phase boundary. In addition, absorption/desorption of H2 is irreversible for this “cycled” Pd. The same phenomena were examined for several substitutional fcc Pd–Mn alloys; supersaturation was also observed for the three alloys: XMn = 0.01, 0.05 and 0.075.