Hydrogen solubility in PdCuAg ternary alloy films prepared by electrodeposition

•Thin films made of PdCuAg are prepared by electrodeposition over the whole composition range.•All compounds are made of single fcc structure.•The hydrogen solubility was measured over the whole compositional range.•The hydrogen solubility increases with the Pd content.•At fixed Pd content, the hydrogen solubility is either constant or decrease when Cu atoms are replaced by Ag atoms.

PdCuAg films were prepared by pulsed co-electrodeposition on Ti substrate. The film composition, determined by energy dispersive spectroscopy ([Pd] = ∼35–65 at.%, [Cu] = ∼35–65 at.%, [Ag] = ∼0–15 at.%) was controlled by varying the electrolytic bath composition. X-ray diffraction analyses showed that all the as-deposited films present a monophased face-centered cubic (fcc) structure with an anisotropic deformation of the crystalline structure. Scanning electron microscopy (SEM) observations indicated that all the films present a cauliflower-like morphology. Their hydrogen solubility was evaluated electrochemically in NaOH media. It was shown that the H solubility in the alloy increases with the Pd content. At fixed Pd content, the variation of the H solubility with the Cu or Ag content is more complex and depends on the Pd content. Lastly, a major decrease of the H solubility was observed for films annealed at 400 °C due to the resulting fcc-to-bcc phase transition.