Study on pulse nickel plating and its property

The effects of pulse duty cycle, average current density and temperature on electrodeposition speed, brightness and corrosion resistance in 3.5% (mass fraction) NaCl solution of nickel coating were studied with a Watts-type nickel electroplating bath. The surface morphology was characterized by scanning electron microscopy. The results showed that the electrodeposition speed was increased with increasing pulse duty cycle, average current density and temperature. The corrosion resistance and brightness were decreased with increasing pulse duty cycle, while they became better at first and worse thereafter with the increase of temperature and average current density. The optimal plating conditions are as follows: average current density 0.75 A/dm2, pulse duty cycle 5%, temperature 45-50 °C, pH 2.5-3.0. Compared with direct-current nickel plating, the pulse-plated nickel has preferential orientation with (111). X-ray diffraction analysis showed that the deposit of pulse nickel plating is more compact and has better performance.