EXPERIMENTAL INVESTIGATION OF TRIBOLOGICAL BEHAVIOUR OF Ni-TiO_2 NANOCOMPOSITE COATING ELECTRODEPOSITED ON AA6061

摘要

In the present study, nickel along with nano TiO_2 particles as reinforcement were deposited on AA6061 to enhance the properties using conventional DC electro co-deposition (ECD) with Watt bath electrolytic solution. The ECD parameters namely current density, particle concentration, stirring speed, bath temperature and pH of the bath were considered as process variables for experimentations designed with Taguchi robust design by choosing L_(27) orthogonal array with the above five plating parameters and three levels to determine the nature of the coating. The results of the experiments were analysed with Minitab16 software to establish the relationship between the input variables causing enhancement of microhardness and reduction of wear rate of AA6061. The effect of ECD parameters was examined with mean effect studies and S/N ratio values for the response of microhardness and wear rate to understand the significances between independent process parameters. It was found that the most important parameter in considered levels was particle concentration for maximum microhardness and current density for lesser wear rate. The analysis of variance (ANOVA) test shows that among the ECD parameters, particle concentration, current density, and stirring speed are the most significant factors influencing the properties of TiO_2 coatings. The surface morphology and composition of coatings are also studied with the help of scanning electron microscopy, energy dispersed X-ray analysis and X-ray diffraction analysis.