Effect of the porous stainless steel substrate shape on the ZrO2 deposition by vacuum assisted dip-coating

The effect of the support shape on the deposition of ZrO₂ by the vacuum-assisted dip-coating method was studied. Disc-shaped and tubular porous stainless steel substrates were used to obtain ZrO₂ coated supports for the synthesis of PdAu alloy composite membranes. The microstructure of the ZrO₂ modified supports was evaluated by scanning electron microscopy and confocal laser microscopy. Besides, a qualitative assessment of the porosity and roughness of the porous substrates was performed by confocal laser microscopy. Dense and continuous palladium-alloy films were deposited on top of the modified tubes after thirteen ZrO₂ deposition-calcination cycles. Cross-section EDS mapping and XRD diffraction analysis showed that a complete PdAu alloy formation was obtained even after annealing at 723 K in hydrogen stream during 5 days.