TECHNOLOGY FOCUS - INORGANIC CHEMISTRY - Preferred Method: The seeding step involves airbrushing a palladium salt solution onto the surface of the substrate, where the palladium salt solution is a solution consisting of palladium (II) acetate and chloroform. The decomposition step includes firing the substrate comprising the palladium crystallites at an elevated temperature to eliminate any organic ligand present. The reducing step involves immersing the substrate in a reducing solution, where the reducing solution is a solution consisting of water, NH3OH and hydrazine. The step of depositing a first film of palladium metal includes pumping palladium plating bath over the surface of the substrate. The pumping continues until a palladium layer having a thickness of 1 to 7 microns is formed; or until a gold layer having a thickness of 1 to 7 microns is formed. The step of depositing a second film of gold includes pumping a gold plating bath over the surface of the substrate, where the gold plating bath is a solution consisting of water, NaOH and gold (III) chloride. The fabrication method further involves depositing a third film of silver on the second film of gold. The step of depositing a third film of silver includes pumping silver plating bath consisting of silver nitrate, NH3OH and water over the surface of the substrate. The depositing steps are conducted in the absence of both organic complexing agents and tin. Preferred Components: The substrate is a stainless steel support having a porous ZrO2 coating. At least one portion of the substrate has been sealed with a low temperature glaze. The palladium plating bath is a solution consisting of water, NH3OH, HCl, palladium (II) chloride and hydrazine. EXAMPLE - Composite palladium-gold (Pd-Au) alloy membranes were fabricated by sequential deposition from palladium and gold electroless plating baths onto symmetric 0.2 microns cut-off alpha-alumina tubes. No EDTA was used in the Pd plating solution to minimize contamination by carbon. When pure gases were used they were nominally 99.999% pure. Prior to palladium plating, the surface of the membrane support was first seeded with Pd particles by impregnating the ceramic support with an organic Pd salt solution, followed by reduction in aqueous hydrazine solution. Pd and Au electroless plating baths were then used in sequence to deposit films of 5 to 7 microns in thickness.