Palladium onto vanadium

The group of Nishimura has evaporated 100 nm thick films of palladium onto both sides of foils of vanadium alloyed with nickel, aluminum and molybdenum in an ultra-high vacuum system equipped for physical vapor deposition [62-66]. 

In one embodiment patented by Makrides et al., tantalum foils were electrolyti-cally etched in hydrofluoric acid, washed with acetone and, while still wet with acetone, placed in vacuum and dried by evacuation. Using an argon plasma at a pressure of about 1 mm Hg (133.3 Pa), palladium was deposited onto both sides of the membranes to recommended thicknesses between 10 and 100 nm. Membranes of niobium and vanadium were prepared in the same manner, except that, in addition, vanadium was degassed in vacuum at 1273 K (1000 °C) to remove oxygen. Unalloyed palladium as well as Pd-Ag, Pd-Au and Pd-B, were also patented as hydrogen dissociation catalysts and as protective layers for the highly reactive niobium, tantalum and vanadium. 

Edlund et al. have used thin foils of palladium or platinum laminated onto Nb, Ta or V substrates. [46-52]. Edlund and Pledger used platinum-vanadium-palla-dium laminated composites at 973 K (700 °C) to decompose H2S at partial pressures up to 115 psia (7.9 bara) and total pressures up to 1000 psi (69 bar) [48]. Removal of hydrogen through the composite membranes aids the decomposition... 

These authors also investigated ways to avoid these low-temperature losses of nickel and vanadyl porphyrins, and found that 20 ptg of reduced palladium, deposited onto the platform before sample introduction, efficiently avoided all losses, and stabilized all nickel and vanadium compounds in oil up to 1300 °C and 1600 °C, respectively [144], as shown in Figure 8.49. 

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