Production of Ni-Co composite coatings by pulse electrolytic method and investigation of tribological behavior

Hard chrome coatings are widely used due to their properties such as hardness, corrosion, wear and heat resistance. However, when hexavalent chromium is electrodeposited, this solution, which is carcinogenic, corrosive, and extremely oxidizing in its aqueous solutions, causes major health, safety and environmental issues. Hard chrome plating's industrial use is limited as a result of this circumstance. The goal of this thesis is to develop a pulse current coating process as an alternative to hard chrome plating, which is one of the hard and wear-resistant surface applications, for Ni-Co and Ni-Co based composite materials. In the thesis study, it was aimed to develop Ni-Co and GO composite coatings added at different concentrations for specific applications. Thus, it was aimed to develop an alternative coating method to hard chrome plating by obtaining coatings with high hardness and wear resistance properties. In this thesis study, composite coatings were produced that were added to the pulse current Ni-Co bath at 25 mg/L, 50 mg/L, 100 mg/L and 200 mg/L, respectively. The surface morphology and cross-sectional images of the coatings produced were characterized by scanning electron microscopy (SEM) and phase analysis using X-ray diffraction (XRD) method. The wear values of the coatings were determined by ball on disc method and the hardness values were determined by nano-hardness system. As a result of the analyzes, the lowest wear rate and the highest hardness value were determined in the coating with the addition of 100 mg/L GO composite.