Structure, composition and corrosion resistance studies of Co–Cr alloy electrodeposited from deep eutectic solvent (DES)

Electrodeposition of Co–Cr alloys on brass and mild steel substrates has been investigated using direct current (DCD) and pulsed electrodeposition (PED) techniques. The alloy contains approximately 65–81% Co, and 19–35% Cr. The aim of this work is to develop a stable deep eutectic solvent (DES) containing Co(II), and Cr(III) ion without any Cr complexing agent. The influences of direct current and pulsed current on the Co–Cr compositions have been investigated. The crystallographic structures, morphology and chemical composition of Co–Cr deposited films are analyzed by means of XRD, SEM, EDS and XPS. The anticorrosive properties of Co80.04Cr19.95 (DCD) and Co65.44Cr34.55 (PED) alloy on mild steel substrate have been studied and compared using potentiodynamic polarization and electrochemical impedance spectroscopy.

► Deposition is from nonaqueous electrolyte, free from complexing agent and H2 reduction.
► The effect of DCD and PED on the structural morphology and composition of Co–Cr alloy was studied.
► PED increases Cr% in Co–Cr alloy with fine grained and nodular deposits.
► PED deposited alloy is having very high Rct than that of DCD technique.