The shape of the polarization curve and diagnostic criteria for the metal electrodeposition process control

Abstract

The simulated shapes of the polarization curves were correlated with the type of metal electrodeposition process control in a function of the exchange current density to the limiting diffusion current density (j₀/j_L) ratios. Diagnostic criteria based on the j₀/j_L ratios were established. For j₀/j_L> 100, the system is under the ohmic control. In the range 1 < j₀/j_L ≤ 100 there is the mixed ohmic-diffusion control. The pure diffusion control appears in the range 0.1 < j₀/j_L < 1. For j₀/j_L < 0.1, the system is activation controlled at the low overpotentials. The proposed diagnostic criteria were verified by comparison of the simulated curves with experimentally recorded ones and by morphological analysis of deposits obtained in the different types of metal electrodeposition process control.