Mechanism of the Electrodeposition of Zinc Alloys Containing a Small Amount of Cobalt

Corrosion resistant Zn‐Co alloys were electrodeposited on the steel sheet cathode from an acid galvanizing bath containing a small amount of cobalt sulfate. Under most of the plating conditions studied, the anomalous codeposition and, hence, the preferential deposition of electrochemically less noble Zn occurred. The electrodeposition process of the alloy including the Zn hydroxide formation resulting from the rise in p H in the vicinity of the cathode was estimated by electrochemical and spectroscopic studies.