Optimized bath for electroless deposition of palladium on amorphous alumina membranes

A new bath for the electroless deposition of palladium on anodic alumina (AA) membranes is proposed. It was found that the optimal conditions for the uniform deposition of palladium, with minimal damage to the AA membranes, were under conditions of pH 8.4 and plating times shorter than 30 min. The deposited Pd layer was detected by X-ray diffraction (XRD) and energy dispersive X-ray (EDX) analysis. The morphology of the AA membrane before and after plating was examined by scanning electron microscopy (SEM). EDX analysis revealed that palladium was deposited only on the surfaces of the membrane and Sn ions, coming from the sensitizing bath, were incorporated into the palladium layer. EDTA incorporated into the palladium layer was also detected by Fourier transform infrared spectroscopy (FTIR). The total amount of palladium deposited was evaluated both by atomic absorption spectroscopy (AAS) and by a new complexometric procedure specifically developed to estimate the quantity of palladium in the presence of aluminium ions.