Preparation of Pulse Electrodeposited Ni-B Coating with RSM Software and Evaluation of Its Microhardness and Electrochemical Behavior

In this study, the electrodeposition parameters were optimized to attain Ni-B alloy coatings with high hardness and corrosion resistance. The optimum plating parameters of the Ni-B coatings to get desirable properties (high microhardness and corrosion resistance) were determined by the response surface method (RSM) software. The effects of the boron concentration, average current density and duty cycle on the hardness of the deposited coatings were evaluated by the Vickers microhardness (HV) tester. The electrochemical behavior of the deposits was studied by electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization (Tafel) methods. According to the results, raising the boron content and current density and decreasing the duty cycle led to increased microhardness (from 707 to 1116 HV) and improved corrosion resistance. Great corrosion resistance of 44 k ohm/cm(2) with a low corrosion current density of 0.121 mu A/cm(2) was achieved at a boron concentration of 11 g/l, current density of 50 mA/cm(2) and duty cycle of 20 pct.