Hierarchical-structured surface and corrosion behavior of Cu–Zr amorphous alloy manufactured by electrodeposition

Abstract

Deep eutectic solvents (DESs) provide enormous opportunities for manufacturing functional, electronegative metal alloys with hierarchical structures—because of the broad working windows for electrochemical reactions and the advantages of multiscale directing chemistry. This work presents the electrodeposition preparation of a hierarchical-structured Cu–Zr amorphous alloy coating from ChCl–EG DES for the first time. The electrochemical behavior of Cu²⁺ and Zr⁴⁺, and the comprehensive microscopic and structural characterizations of the obtained deposits, demonstrate a potential-dependent nucleation and growth mechanism of Cu and Zr species on the surface of Cu foil. The deposits yielded at the lower negative potentials containing small amounts of Zr (< 4.0 at.%) are two-phase, with fibrous Cu_aZr_bO_c compounds cross-growing on the surface of the leaf-like face-centered cubic Cu phase. In contrast, the deposit obtained at a higher negative potential presents a Christmas tree-like Cu–Zr amorphous alloy structure (9.03 at.% Zr), and the hierarchical multiscale ZrO₂ amorphous layer formed on its surface can enable the native alloy with better corrosion resistance.