Zinc barrel electroplating using low cyanide electrolytes

The influence of plating conditions on the cathode efficiency of zinc barrel electroplating and the quality of deposited layers for low cyanide electrolytes is analysed. The investigations are carried out using factorial design methodology. The first part of the study shows how electrolyte components, such as brightening agent, sodium carbonate concentration, sodium hydroxide concentration, sodium cyanide concentration and zinc metal content, influence cathode efficiency and the morphology and the texture of the zinc electrodeposits. A mathematical model that fits experimental data is suggested and the pseudo three-dimensional plot of yield as a function of electrolyte composition for three significant component mixtures, brightening agent, sodium cyanide concentration and zinc metal content, is represented. The second part of the study shows how varying six process parameters influences current efficiency and metal thickness distribution. For the range studied, efficiency is affected by workload volume, current density, perforation and part size, but not by rotation speed and quantity of charge.