Electrical resistivity, strain and permeability of Pd–Ag membrane tubes

On alloying and low-temperature stability of thin, supported PdAg membranes

“…For example, Tosti et al reported an elongation of ca. 1.5% for a 200 mm thick Pd 75 Ag 25 membrane tube during hydriding under 200e400 kPa H 2 at 373 K and below [23]. Thus the repeated low-temperature H 2 adsorption and desorption is every time accompanied by a substantial expansion and shrinking of the PdAg membrane.…”

Hydrogen Absorption in Pd–Ag Systems: A TPD and Electrical Resistivity Study

“…Conversely, in Pd–Ag alloys, the lattice has already been expanded by the silver atoms, so it is less influenced by hydrogen uploading and, consequently, less brittle than the pure Pd [1]. The alloying with Ag also improves the mechanical properties and the hydrogen permeability [5]. In fact, both the tensile strength and the permeability show a maximum for a silver content in the range 20–40 wt.%, a content of Ag in the commercial Pd alloys used for membrane applications.…”

“…Among different design configurations, the direct ohmic heating of Pd–Ag permeator tubes has been studied. Such an arrangement permitted the reduction of power consumption with respect to the traditional membrane module heating systems and shortened temperature ramping [5]. These applications evidenced the need to study the effects of the metal/hydrogen interactions on the electrical resistivity of the Pd alloy in more detail.…”

A basic study of high-temperature hydrogen permeation through bcc Pd–Cu alloy foil

“…However Pd metal, whose lattice structure is face-centered cubic (fcc), suffers problems such as ß-phase formation in the presence of hydrogen below its critical temperature of 298°C and hydrogen embrittlement, causing defect formation on the membrane [5]. The use of a Pd-Ag alloy mitigates these problems [5], but the hydrogen absorption causes fcc-lattice expansion leading to the defect formation [6]. Also, the poisoning by sulfur is an indispensable problem during the actual operation of the reactor [5].…”