Prediction of metal distribution in electroplating systems

Three methods of approximation were developed to predict the metal distribution in electroplating systems. The results were compared with Watson's experimental data for the Watts-nickel (close to 100% current efficiency), tin-nickel (alloy deposition, also close to 100% current efficiency), and the standard chromium (approximately 20% current efficiency) systems. Method 1 predicted too uniform a distribution whereas Methods 2 and 3 showed good agreements with all three systems. The same experimental data were also used to evaluate three predictive methods frequently used in the literature. The primary current distribution and an empirical formula by Hull were found to be inadequate in describing these systems. The secondary current distribution which involved a great deal of numerical analysis showed a considerable improvement.