Honeycomb-like porous metallic glasses decorated by Cu nanoparticles formed by one-pot electrochemically galvanostatic etching

Pitting corrosion is a common localized corrosion phenomenon, which can lead to cracks and mechanical failure in structural metal materials. On the contrary, pitting corrosion could be a beneficial tool for generating large-area porous structures, which holds a great premise in a number of functional services, such as catalysis, sensing, storage, imprint lithography, and membranes. Herein we presents an electrochemical approach for creating a large-area honeycomb-like porous structure in Zr-based metallic glasses. A pitting process followed by subsurface tunnel etching in NaCl solution elicits to characteristic micrometer scale channels and nanometer size amorphous sidewalls decorated by Cu nanoparticles on the metallic glass substrate. A root-shape growing mechanism of tunnels initiated from pits and penetrating into alloy matrix is postulated. In addition, the effect of alloy composition on the microstructure of honeycomb-like porous metallic glasses is also investigated in detail.