Dense PdAgCu ternary alloy composite membranes were synthesized by the sequential electroless plating of Pd, Ag and Cu on top of both disk and tubular porous stainless steel substrates. X-ray diffraction and scanning electron microscopy were employed to study the structure and morphology of the tested samples. The hydrogen permeation performance of these membranes was investigated at 350 to 450C and trans-membrane pressures of up to 100kPa. After annealing at 500C in hydrogen stream followed by permeation experiments, the alloy layer presented a FCC crystalline phase with a bulk concentration of 68%Pd, 7%Ag and 25%Cu as revealed by EDS. The PdAgCu tubular membrane was found to be stable during more than 300h on hydrogen stream. The permeabilities of the PdAgCu ternary alloy samples were higher than the permeabilities of the PdCu alloy membranes with a FCC phase. The co-segregation of silver and copper to the membrane surface was observed after hydrogen permeation experiments at high temperatures as determined by XPS.

Novel PdAgCu Ternary Alloy: Hydrogen Permeation and Surface Properties. A.M.Tarditi, F.Braun, L.M.Cornaglia: Applied Surface Science, 2011, 257[15], 6626-35