Seramik takviyeli Ni-Cu metal matris kompozitlerinin üretimi ve karakterizasyonu

Ni-Cu alloys have been widely used for various application areas with their non-toxic nature, low cost, and easy availability in nature. Although Ni-Cu based coatings have advantages, they need to be developed to improve their limited mechanical properties and limited corrosion resistance. Ni-Cu based coatings can improve their properties by forming composite materials with various additives. In this study, CeO2 reinforced Ni-Cu metal matrix composites were studied with different electrochemical deposition modes to understand the influence of the electrodeposition modes on the structural, compositional, morphological, mechanical, and electrochemical properties of the metal matrix composites. The cyclic voltammetry was analyzed for the CeO2 containing electrolytes to understand the reduction behavior of the metal ions and ceramic particles. Later potential controlled (pulse potential current) and current controlled (direct current and pulse current) electrodeposition of the Ni-Cu/CeO2 layers performed on SS316 foils from a simple sulfate-based electrolyte at 50°C. It has been found that the hydrogen evolution reaction was less for the CeO2 containing electrolytes which are essential to obtain smooth surfaces. Besides that, it has been found that electrochemical deposition parameters are dramatically influencing the morphological, compositional, and structural properties, hence the mechanical and electrochemical properties. The distribution of the CeO2 particles was influenced by the pulse current duty cycle and pulse current frequency. Moreover, the Ni/Cu ratio was affected by the pulse current duty cycle and pulse current frequency. But most importantly, it has been found that it is possible to modify the existing phases, Cu-rich, Ni-rich, and Ni-Cu solid solutions by changing the pulse current deposition modes. The mechanical and electrochemical properties of the layers suggest that there are multiple factors influencing the hardness and corrosion resistance of the samples. It has been found that besides ceramic particle amount, the morphology, existing phases, and the Ni/Cu ratio are also influencing the hardness and the corrosion resistance of the samples. The morphology of the samples became more compact with the CeO2 reinforcement for all the samples. More uniform particle distribution was observed at low frequencies and with low duty cycles. The hardness of the samples was influenced by the amount of CeO2 loading together with the Ni-Cu ratio. It has been found that lower Ni/Cu ratios are resulting in improved corrosion resistance which indicates Cu-rich samples were more resistant to corrosion. The optimum condition was observed for direct current electrodeposited Ni-Cu/CeO2 samples with Ni-Cu solid solution which had smooth and compact cauliflower-like formations, low Ni/Cu ratio, and low crystal sizes that resulted in relatively high hardness and corrosion resistance.