1988 Volume 74 Issue 12 Pages 2307-2314
Factors affecting zinc electrodeposition on conductor roll (CDR) in a horizontal electroplating cell were investigated. Zinc electrodeposition on CDR was basically attributed to leak current from anode to CDR through plating bath. Limiting current density of hydrogen evolution was also a dominant factor affecting zinc electrodeposition on conductor roll. A decrease in the leak current and an increase in the current density of hydrogen evolution reduced zinc electrodeposition on CDR. The leak current depended on electroplating cell parameters including the distance between CDR and anode, the electrode gap, anode length and solution level from strip. The current density of hydrogen evolution was affected by bath composition and pH of the bath. Decreasing pH of sulfate bath increased the current density of hydrogen evolution.Prevention of zinc electrodeposition on CDR was not achieved only by lowering pH of sulfate bath down to 1 in the cell used for the experiments. It was attained by applying CDR shielding method using covers made of insulator neighboring on CDR in addition to using sulfate bath of pH=1.