Coating of aluminum substrates with nanostructured Pd–Ni alloys by electrodeposition

Abstract

Pd–Ni alloys are electrodeposited onto low-purity aluminum substrates varying both the composition of the feeding solution and the applied electrodeposition potential. It is found that the initial nucleation-and-growth mechanism in every case is well described by a 3D-type nucleation process. The resulting deposits consist of Pd–Ni alloys of different compositions, all electrocrystallized in a disordered fcc phase; depending on the electrodeposition parameters, different morphologies and compositions are obtained. It is found that when the electrodeposition potential is high and the Pd content in the feeding solution is low, the substrate coating is more efficient and the deposit morphology tends to refine into dendritic-like structures, making this kind of deposit quite interesting for using as electrodes in electrochemical devices. Room temperature magnetic measurements indicate that the samples are soft ferromagnetic with negligible demagnetizing effects. Dendritic and spheroidal-like Pd-rich deposits exhibit larger remanence values and are more coercive than those with higher Ni content due to the dependence of the anisotropy constant on the alloy composition.