Preparation and properties of electrodeposited Ni-TiO2 composite coating

Abstract

Mechanical properties of cutting tool like microhardness, coating adhesiveness & corrosion resistance are some important parameters, which affects the tool life and further indirectly affects the component cost. In this paper Ni-TiO₂ composite coating was prepared through electrocodeposition in order to improve the mechanical properties of tungsten carbide cutting tools. Microhardness of Ni-TiO₂ composite layer have been studied by varying input current density (mA), pH vale of electrolyte & particle concentration of TiO₂ in electrolyte bath. Microstructure and phase structure of composite layer were investigated using atomic force microscope (AFM), scanning electronic microscope (SEM) and X-ray diffraction (XRD). Surface morphology of Ni-TiO₂ coated layer shows fine grained structures is obtained at low currents with higher microhardness of composite coating. Maximum microhardness 1483 HV of coated layer is found at 15mA of current and at 4.5 pH of watt’s solution. It has also been seen that with the increase of Ti, microhardness of the layer is also increases.