電析法によるPt-Ni合金薄膜の作製

抄録

In order to enhance the electrocatalytic activities of a hydrogen electrode and lower the price of the electrode, the possibility of Pt-Ni alloy plating as the electrode material formation was studied. It is generally hard to codeposit Pt and Ni, because they have considerably different standard oxidation-reduction potentials. Complexing agents were surveyed to bring the oxidation-reduction potentials of both Pt and Ni closer by drawing immersion potential-pH diagrams. Glycine was found to be useful for Pt ion as a complexing agent. The best electroplating condition was determined by measuring the current-potential curves of Pt and Ni ions and analysing the composition of the deposits. The plating bath composition was investigated by changing the Ni concentration and pH. The optimum bath composition and conditions were 0.009mol/dm³ NiCl₂·6H₂O, 0.001mol/dm³ K₂[PtCl₄] and pH4. It was confirmed by XRD analysis that the plating film obtained at optimum conditions was a Pt-Ni alloy. By changing the current density of the electroplating from 0.15A/dm² to 1.0A/dm², thin Pt-Ni alloy films could be obtained with Ni content between 35mol% and 67mol%. The film thickness obtained in this study was between 0.42μm and 0.75μm, and each metal was distributed uniformly on the surface and also in the depth direction.