Study on micro structure and wear behavior of Zn- Ni alloy coatings

Zn–Ni alloy coatings were electrodeposited from an acidic sulfate bath, while their microstructures, corrosion properties and wear behavior were investigated. To study their structures, X-ray diffraction (XRD) was used. To evaluate the wear behavior, wear tests via pin-on-disc were performed. Hardness measurements were carried out via Vickers microhardness testing machine. Secondary and backscattered electron micrographs were taken from the worn surfaces and chemical compositions of the coatings were also investigated using Scanning Electron Microscope (SEM) equipped with Energy Dispersive Spectroscopy (EDS) analyzer. X-ray diffraction (XRD) technique was also used to determine the phase structures of the coatings. The results indicated that the amount of nickel in the coating had a strong impact on their properties so that by increasing the amount of nickel an increase in the coating hardness was obtained. Finally, Zn-14% Ni coating which contained a single phase -Ni5Zn21 face centered cubic had the lowest coefficient of friction as well as wear rate among all other coatings with different chemical compositions.