Palladium sequential deposition

In case an alloy is formed, such as palladium-silver or palladium-copper, either metal co-deposition (Cheng and Yeung, 1999 Huang et al, 2003) or sequential deposition can be made (Kikuchi and Uemiya, 1991 Ma et al., 2004) in both cases, however, an annealing treatment should be made to obtain alloying by intermetallic diffusion (Uemiya et al., 1991b Roa etal.,2003). 

Individual deposition of the Pd and Ag was also undertaken using an electroless method. By plating each metal individually the process can be controlled to obtain a range of different metal ratios. Again, the compositions of the plating solutions and the deposition methodology have been detailed elsewhere (Brown et al., 2010 Wu et al., 2010b). The components of the solutions were the same as the co-deposition solutions except for palladium where a chloride salt was used in place of the nitrate. Membranes that were coated with Pd only were used to compare with the bimetallic sample. Samples were also plated with Pd then sequentially with Ag as comparisons for the co-deposited samples. 

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