Premium
A predictive model for the time dependence of concentrations in plating baths
Author(s) -
Baumer Christoph,
Bund Andreas,
Herrmann Johannes
Publication year - 2019
Publication title -
journal of chemometrics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.47
H-Index - 92
eISSN - 1099-128X
pISSN - 0886-9383
DOI - 10.1002/cem.3166
Subject(s) - electrolyte , galvanic cell , electroplating , dilution , plating (geology) , chemistry , nonlinear system , nucleation , deposition (geology) , drag , thermodynamics , process engineering , materials science , electrode , metallurgy , physics , paleontology , organic chemistry , layer (electronics) , quantum mechanics , sediment , geophysics , biology , engineering
An industrial electroplating process is usually based on a long‐term and intensive use of the electrolytes. In most cases, ten to several hundred metal turnovers (MTO) are deposited from a commercial bath. As a consequence, the composition of the electrolyte can change drastically during its use. Furthermore, some bath components are difficult to determine and therefore are not analyzed routinely or not analyzed at all. In this paper is shown how the control of the electrolytes can be realized by mass balances and analyzing of the main components. For this purpose, a nonlinear model for the calculation of the concentration considering drag‐out and the reaction mechanism is defined. Based on this model, the composition of the electrolyte is simulated considering the replenishment and dilution of the bath. By using simulated annealing, the simulated concentrations are fitted to the real concentrations. Based on the known reaction system, the normally unknown characteristic parameters of the deposition like drag‐out, deposited mass, current efficiency, and alloy composition are obtained. These values can then be used for improving process control and calculations of regular additions of bath components. Additionally, this procedure describes a general systematic to validate hypothetical considerations of the reaction mechanism in a galvanic process by practical data.