Plasma Chemistry and Plasma Processing, Vol.37, No.1, 177-187, 2017
Cathodic Plasma Electrolysis Processing for Metal Coating Deposition
Cathodic plasma electrolysis (CPE) is used to deposit Zn coating on the surface of steel wire. The relationships between power parameters and coating characteristics were investigated in this study to determine the best way to control the coating process according to the CPE procedure and pulsed DC power cycle. We found that voltage should be greater than the critical voltage for the formation of plasma. Deposition coating is difficult to establish under DC supply, however, continuous coating is rather easily prepared under pulsed DC power of 120 V, 4000 Hz, and 80 % duty cycle. We adopted pulsed DC power to successfully facilitate Zn cations approaching the cathode surface as well as to prevent wire melting under high voltage by reducing the duty cycle. Decreases in voltage, frequency, or duty cycle did not contribute to plasma stability, but did increase the deposition rate and porosity. Our experimental plasma formation process showed that the role of plasma formation is to clean the cathode surface by melting and shocking, which produces deposition at the interval between two neighboring pulses.