Studies on surface treatment of electrodeposited Ni–Zn alloy coatings using saccharin additive

Abstract

Ni–Zn alloy coatings were electrodeposited galvanostatically at room temperature. Saccharin (0 to 1.8 g L−1) was added in the deposition bath as an additive agent. The effects of varied saccharin content addition on the physical properties of Ni–Zn alloy coatings were studied. The Ni–Zn alloy coatings were characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM), atomic absorption spectroscopy (AAS), atomic force microscopy (AFM), contact angle, electrochemical impedance study (EIS), salt immersion test, friction coefficient, and wear resistance tribology techniques. The XRD study confirmed the formation of Ni–Zn alloys with mixed phases of Ni–Zn alloy depending upon the saccharin content addition. The AAS analyses based on varied saccharin addition confirmed Ni–Zn alloy composition between 64:36 and 22:78 at.%. The effects of varied saccharin addition on physical properties like stress, strain, microstructure, topography, wettability, wear, and corrosion resistance were studied. The optimized 1.6 g L−1 saccharin addition in the deposition bath with Ni–Zn composition as 25:75 at.% possesses highly enhanced surface properties like compact, smooth microstructure, and increased corrosion resistance with reduced friction coefficient value.