Physicochemical and corrosion properties of sono-electrodeposited Cu-Ni thin films

Abstract

Cu-Ni thin films were electroplated from a bath containing fixed amount of Ni and three different concentration of copper in order to make Cu:Ni molar ratio of 1:10, 1:15 and 1:20 in static and ultrasonic condition. Electrochemical characterization i.e. cyclic voltammetry (CV) was done to know the reduction potential range for Cu-Ni co-deposition. Corrosion study revealed that films synthesized under static condition had better corrosion protective behavior as compared to films in ultrasonic condition. X-ray diffraction (XRD) patterns were recorded and it showed that alloying was better in presence of ultrasound. Surface morphology was examined by scanning electron microscopy, atomic force microscopy and composition analysis was done by energy dispersive spectroscopy (EDS) studies. Both morphology and composition showed a strong dependence on bath concentration and ultrasonic irradiation. EDS analysis showed that the films are Ni rich in static condition and Cu rich in presence of ultrasound. Hardness was tested by Micro-Vickers hardness tester where films in presence of ultrasound were found to have better hardness value due to refined grain size. Thickness and residual stress of the films were measured by Stylus surface profilometer. Film thickness varied from 1.98–2.16 μm in static condition which got increased to 2.69–3.59 μm in presence of sonication for equal period of deposition. Residual stress analysis reported a stress value ranging from 172.43 to 273.18 GPa in static condition which showed a remarkable decrease to 35.25–82.34 GPa in ultrasonic condition.