چكيده به لاتين
This process is performed by using two direct and pulsed direct current. Electroplating Ni-Zn alloy coating has been considered due to the creation of abrasion resistant layer, soldering ability, good electrical conductivity and good adhesion, decorative appearance and high corrosion resistant coatings in the aerospace, automotive, food, and mobility portions. In this research, a comparison was made between electroplating of nickel-zinc coatings produced from Watts bath using direct and pulse current in the range of frequencies from 0.1 to 100 Hz, duty cycle of 20% to 100% and Average current density 2 to 4A/dm2. The weight ratio of nickel ion sulfate salt to zinc in the plating bath is considered to be 100, and the total atomic ratio of nickel ion to zinc in the bath is 126, while this ratio measured 15/5 times as high as in alloy coating that shows the plating of this alloy is classified as anomalous codeposition. After analyzing the results, it was found that the coatings produced by the puls method than direct have a finer grain size, a higher uniformity and a lower thickness. Also, the coatings obtained by this method have a crystalline size of about 21/4 nm and by decreasing applied duty cycle, increasing the current density and reducing the frequency, in mentioned range, the percentage of nickel deposited in the range of 60.3% (for direct current) to 96.2 (for pulse current) and the corrosion resistance of the coating measured by the polarization test and EIS, is also increased.
