Affection of Cu content on the phase evolution during the dealloying of Ag-Cu alloys using electrochemical noise with Hilbert spectra analysis

The affection of Cu content on the phase evolution of Ag-Cu alloys was investigated by electrochemical noise (EN) with Hilbert spectra analysis. The results showed that the dealloying corrosion rate decreased and contribution of the transient shift from low-frequency parts (diffusion process) to the high-frequency parts (dissolution process) increased with the content of Cu increasing. Due to the increasement of Cu content, amounts of the Ag2Cu phases would be promoted. Ag2Cu phases had higher potential contrast with Cu phases and promoted the formation of different phase boundary, and different phase boundary would inhibit the diffusion of Ag atom. Thus, the hypoeutectic Ag15Cu85 alloys performed highest dealloying corrosion rate and the contribution of the transient at the highest-frequency parts followed by Ag20Cu80 and Ag25Cu75 alloys.