Nickel electroplating control in the mode with current reversal considering its limiting frequency

Using reverse current during electroplating can increase the uniformity of the obtained coatings. When electroplating in a mode with reverse current the variable parameters are amperage of direct and reverse current as well as their pulses duration. For research process in this mode, the limits of variation of pulse duration or process frequency must be set. Frequency limit of the process can be found by providing a plating bath in the form of an equivalent circuit and by determining the bandwidth of the resultant circuit. The bandwidth is determined from the module of transfer function system. Its value can be found by conducting an experiment and determining the value of the constituent elements of the equivalent circuit using the techniques described in this research. The limited values of duration of direct and reverse currents for nickel electroplating process during the mode with current reversal are obtained. Available equipment does not allow experimental studies with obtained pulse durations. The device of current reversal with characteristics allowing conduction of experiments with pulse duration of 1 ms has been designed. Based on the device a computerized control system of electroplating process in the mode with current reversal is made. Application of the created system has improved the uniformity of the coating by 18.9 %, compared to plating using only a direct current.