Permeability, hydrogen through palladium

H. Yoshida, S. Konishi and Y. Naruse, Effects of Impurities on Hydrogen Permeability through Palladium Alloy Membranes at Comparatively High Pressures and Temperatures , J. Less-Common Metals, 89 429-36 (1983). 

Measurement of palladium membrane permeability. The permeation rate of hydrogen gas through the palladium membrane, Q , was assumed to obey the half-power pressure law(20). The permeation flux of hydrogen through the membrane is proportional to the difference between the souare roots of the hydrogen partial pressure on the high and low pressure sides of membrane. 

Yoshida, H., Konishi, S., and Naruse, Y., Effects of impurities on hydrogen permeability through palladium alloy membranes at comparatively high pressures and temperatures, J. Less-Comm. Met., 89, 429, 1983. 

In palladium-silver alloys, larger amounts of hydrogen can be solubilised because the metal lattice has already been expanded by the silver atoms, and thus it is less brittle than the pure Pd lattice. Based on these considerations, the ideal silver content of the Pd cathode is between 20 wt% and 30 wt%. In order to obtain high flow rates of pure hydrogen, the maximum permeability of the Pd-Ag cathode must be realized. The hydrogen permeability P through the lattice of the Pd-Ag tubular electrode follows Sieverts law. The H2 permeating flow rate Qp (mol s ) can be derived from Equation [16.2] ... 

The influence of temperature upon the permeation velocity of hydrogen through iron and through palladium (53) shows that the rate of flow rises exponentially with the temperature The slope of the curves log (permeability) against 1/T(T = K.) for the Hg-Fe system (Fig. 71) is the same at all current densities from 0-0075 to 0-045 amp./cm., and is very nearly that found for the thermal j)ermeability ( eiect. = caL/atom,... 

Collins and Way (1993) have correlated their H2 permeation data successfully with n = 0.573 for a 17 pm palladium film at two different temperatures (see Table 3.P.6). Determine an average value of the hydrogen permeability Qhzbi through the palladium film at the two temperatures. 

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