Deep eutectic solvent-assisted synthesis of a 3D nanoporous surface on Zr-based amorphous alloy

Improving the biomineralization activity of Zr-based amorphous alloys is key to advancing their use in implant materials. A nanoscale 3D porous structure was synthesized on the surface of Zr-based amorphous alloy by electrochemical dealloying in a ChCl-Thi DES. Cu and Al have the lowest corrosion potential in the DES, so the main elements eluted during dealloying are Cu and Al. After dealloying, the surface of the Zr-based amorphous alloy remained essentially amorphous, and several crystalline phases of NiZr2, Al3Ti, and CuZr2 formed simultaneously. Among the amorphous phases, Cu and Ni were present in the form of simple substances, while Zr, Al, and Ti were oxidized. The formation of the porous structure mainly included the two processes of pitting corrosion and dealloying. The pitting corrosion was controlled by Cl-, which can destroy the passivation film. In the dealloying process, thiourea played a leading role in the dissolution of active metals. A porous surface structure is beneficial for improving the biomineralization activity of Zr-based amorphous alloys.