Study of the mechanical and structural properties of Zn–Ni–Co ternary alloy electroplating

Abstract

Ternary zinc–nickel–cobalt alloys were electrodeposited on steel substrates from sulfate bath by direct current. Microstructural and mechanical properties of Zn–Ni–Co ternary alloy coatings were investigated and contrasted with the characteristics of Zn–Ni and Zn–Co alloy coatings. It was found that the obtained Zn–Ni–Co alloy exhibited more preferred surface morphology and mechanical properties as compared to the other alloy coatings electroplated at the same conditions. X-ray diffraction studies showed that the deposits of Zn–Ni–Co alloy coatings consisted of Zn, ZnNi3, and ZnCo13 phases. The structure, surface morphology, and surface topography of the deposited alloys were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) with energy dispersive X-ray microanalysis (EDS), and atomic force microscopy (AFM). In addition, hardness, elasticity modulus, and adhesion strength of coated alloys were measured with dynamic ultra-microhardness (DUH) and Scratch tester.