Dependency of the formation of Au-stabilized nanoporous copper on the dealloying temperature

• Surface diffusivity, pore size increased with dealloying temperature.
• Au accumulation suppresses the formation of rough nanopores.
• Activation energy of Au-added ribbons was 56.1–62.7 kJ mol−1.
• The activation energy of Ti–Cu–Au alloys comes close to that of gold in acids.

Au-stabilized nanoporous Cu with a pore size of 7–24 nm was fabricated through the dealloying of amorphous Ti60Cu40−xAux alloys (x = 1, 2 at%) in HF solutions at 298, 323 and 348 K. Nanoporous structures with larger sizes of bi-continuous pore-to-ligament were obtained at higher temperatures. The residue was confirmed to be crystalline fcc Au and a Cu–Au solid solution. The surface diffusivity of Cu adatoms decreased more than 4 orders of magnitude due to the involvement of Au atoms as the temperature decreased. The surface diffusivity had a linear dependence on the reciprocal of the temperature, in accordance with the Arrhenius law. The activation energy of surface diffusion for amorphous TiCuAu alloys was estimated to be 56.1–62.7 kJ mol−1, which was independent of the Au content and the concentration of the HF solutions.

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