Synthesis and Characterization of Nickel and Ni-TiO ₂ Nanocomposite Coatings Processed by Pulse Electro-deposition Technique

Nickel electroplating is commonly used with substrates including steel, aluminum, plastic and zinc die-cast parts because of its high resistance to temperature, corrosion and wear in harsh conditions. To further enhance its tribological and mechanical properties, research works are going on to produce nano-reinforced composites of Ni with various ceramic and rare earth oxides like CeO₂, ZrSiO₄, SiC, TiO₂, etc. The aim of present work is synthesis and characterization of Ni films and Ni based TiO₂ nano-composite coating processed by pulse co-electrodeposition technique. Also, to investigate the various properties such as mechanical, wear and corrosion resistance, conductivity & thermal stability of Ni-TiO₂ nanocomposites electrodeposited on steel substrate, especially the effects of the amount of nanosized TiO₂ particles in Ni-TiO₂ nanocomposites. The nanocomposite thin films have been characterized by x-ray diffraction (XRD) and scanning electron microscopy (SEM) equipped with an energy dispersive x-ray (EDS). A threshold addition of reinforcements is observed to aid in optimizing the mechanical and tribological properties of the composite. The micro hardness of composites is evaluated and compared with that of pure nickel deposited under same condition. Composite reinforced with 15 wt% nano-sized TiO₂ particulates yielded the best overall properties. Also improvement in thermal stability was observed with increase in TiO₂.