The Influence upon Throwing Power of the Acidic Zinc Bath Composites

The throwing power of commercial acid zinc plating solutions is examined and the major factors that affect throwing power are discussed. The effect of the concentration of bath constituents on throwing power is shown in terms of conductivity and cathode efficiency. As the concentration of zinc chloride is decreased, the conductivity increases until a maximum value is reached and, upon further decrease, the value decreases very slowly. The cathode efficiency decreases with the decrease of concentration. Finally, the throwing power increases with the decrease of concentration rather slowly at first and then rapidly later, forming the plateau portion