Absorption isotherms for H2(D2)–Pd0.8Ag0.2 (198–323K)

Pd-Ag Electrical Resistivity in Hydrogen and Deuterium: Temperature Effect

“…In contrast, at 100 kPa and a temperature lower than 200 °C, Sieverts’ law cannot be applied and Equations (6) and (7) assess solubility values lower than those experimentally measured. In the literature, the analysis of pressure composition isotherms [18,21,22,23] showed a sloping-plateau region distinct for H 2 and D 2 . It is also evident that deuterium equilibrium pressure is higher than that of hydrogen at all experimental temperatures because of an inverse isotopic effect (pD 2 > pH 2 ).…”

“…In this study, both H/M [22,30,40,42,43,44] and D/M [18,21,22,23,31,45] were extrapolated by literature data on the same kind of alloy in order to compare solubility with resistivity data. The literature evidenced that at 100 kPa for low temperatures (25–70 °C) the D/M approaches the H/M value, while increasing the temperature (75–200 °C) causes the D/M to decreases faster, and only at high temperature (>300 °C) do both curves (H and D) tend to converge to very low values (close to zero).…”

“… ρ i vs. temperature for Pd-Ag 21 wt.% in pure hydrogen (red) and deuterium (blue) and relative H/M (red) and D/M (blue) values at 100 kPa. The literature data for D/M: (+) [18], (◯) [21], × [22], (△) [23], (☐) [45] are also shown. Vertical dashed lines show the limits for the different regions A, B, and C in pure hydrogen (red) and deuterium (blue).…”

“…Mitsuishi et al [17] studied the permeation of H 2 , HD, and D 2 for H 2 -Ar, D 2 -Ar, and H 2 -D 2 -Ar systems through a Pd-Ag-Au alloy tube at 400 °C. Luo et al [18] measured isotherms for H 2 /D 2 -Pd 0.8 Ag 0.2 over a low temperature range, −75 to 50 °C. The H/D isotopic effect and the separation factors in the plateau range have been calculated and discussed along various isotherms.…”

Experimental determination of phase equilibria and reassessment of Ag–Pd system

“…The thermodynamic parameters of the new reassessment are given in Appendix and may be used for more exact thermodynamic studies of the Ag-Pd alloys used for hydrogen storage material. The new Ag-Pd thermodynamic parameters may be also useful for the hydrogen diffusion study in these alloys [17,24,25] and for a better understanding of solder joints.…”