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

Abstract

The simulated shapes of the polarization curves were correlated with the type of metal electrodeposition process control as a function of the ratio of the exchange current density to the limiting diffusion current density (j(0)/j(L)). Diagnostic criteria based on the j(0)/j(L) ratios were established. For j(0)/j(L) > 100, the system is under the ohmic control. In the range 1 LT j(0)/j(L) LT = 100, there is mixed ohmic-diffusion control. Pure diffusion control appears in the range 0.1 LT j(0)/j(L) LT = 1. For j(0)/j(L) LT = 0.1, the system is activation controlled at 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 under the different types of control of the metal electrodeposition process.