Investigation of hardness and wear behavior of Ni-BW/AL2O3 composite coatings produced with pulse co-electrodeposition method

Coatings that increase the wear, corrosion and fatigue resistance of materials are used in all areas of our lives. Hard chrome plating, one of the existing used coatings, increasingly restricted considering its human health and environmental effects. In this context, it is important to create alternative coating compositions to hard chrome coatings. Electrodeposited nickel-boron-tungsten (Ni-B-W) alloys, which are offered as an alternative coating material by the US Environmental Protection Agency Research and Development Office, are the coatings that come to the fore today. In this thesis study, four different concentrations (5, 10, 15, 20 g/L) Al2O3 particle reinforced Ni-B-W composite coatings were produced. As the coating method, pulse co-electrodeposition method (PED), which provides more controlled deposition, was preferred instead of the generally used direct current method. Surface, cross-section, post-wear images and elemental analyzes of the produced coatings were performed by scanning electron microscopy (SEM) and Energy dispersive X-ray spectroscopy (EDS) techniques, respectively. Phase analyzes were determined by X-ray diffraction (XRD) technique, while hardnesses before and after heat treatment were determined by Vickers microhardness measurements. In the analyzes made, it was determined that the increase in hardness and wear resistance of coatings containing four different concentrations of Al2O3 particles was maximum at a concentration of 15 g/L. It was observed that the reinforcement at higher concentrations did not have the same effect, on the contrary, a decrease in hardness and wear resistance was observed and it was revealed that the most suitable Al2O3 reinforcement concentration for Ni-B-W coatings was 15 g/L.