Mechanochemical synthesis, thermal stability and selective electrochemical dissolution of Cu–Ag solid solutions

Abstract

Supersaturated nanocrystalline (16–19 nm) Cu 50Ag 50 and Cu 70Ag 30 solid solutions are synthesized by high-energy ball milling. Varying the milling time fcc solid solutions with different lattice parameters are obtained. Thus an increase of the lattice constant that levels off after 20 h of milling is registered for the Cu 50Ag 50 solid solution. At the same time broad overlapped exothermic effects in the temperature range of 170–370 °C are detected by DTA. These can be associated mainly with solid solution decomposition and a grain growth process. Electrochemical selective dissolution reveals a quasi-critical potential of Cu dissolution in Cu 70Ag 30 that is shifted 40 mV positively, compared to the dissolution potential of pure Cu, thus ascertaining the Cu (Ag) solid solution formation. The linear area development with the in-depth progress of the Cu dissolution front confirms the dealloying applicability for fabrication of nanoporous Ag structures in this case.