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M. Moats and T. Hymer
will enable a person to make changes to the process. The operational changes will
polarize or depolarize the reactions, which in turn will impact the deposit morphology
and structure.
Eventually, an operator will come to understand not only the effects of process
chemistry and current density, but also the type and frequency of maintenance that
will help produce quality deposits that are easy to strip and produce higher in CE.
These will ultimately improve the operation’s productivity.
These correlations and internalization of lessons learned from “reading the metal” do not happen overnight. It requires time and dedication. The hope is that the
following information will inspire operators and engineers to travel a path to gain
insight and enable them to apply science to real life situations in a cellhouse and
know what to do to improve their bottom line.
Cellhouse Parameters
Within a cellhouse are a variety of different parameters that impact the plating process. Some are readily changeable and others are not. A zinc cellhouse typically has
a variety of flow rates that can be changed, temperature control, copper bus bars carrying current that can be changed, Zn and acid concentrations, cell voltage, cathodes,
anodes, and additives that are can be added to the system. In addition, the electrolyte
will carry impurities from the leaching process that were not fully removed in purification. All of these items can have an impact on the performance of the cellhouse. A
good practice is to collect all this information daily to see how the process changes
and begin to determine the root causes of deposit structure changes and their impact
on performance. A cellhouse is typically designed to have basic operating parameters
and certain process design that may or may not be changed by the operator. However,
even the parameters that are not readily changeable by an operator can be altered due
to improper maintenance or equipment failure and therefore impact other parameters
and change the conditions to make a proper deposit. Studying and understanding the
intercorrelations between all these items will enable informed decisions on changes
in the cellhouse.
Parameters Impacting Polarization
There are certain parameters that are within the control of the operator to increase or
decrease polarization which can be changed to improve the structure of the deposit.
The main parameters are shown in Fig. 4d. There are two groups—those that increasing their value will polarize and those that depolarize the cathode potential. These
parameters can be considered as “levers” that can shift the potential of the cathode.
Some of these parameters are more readily changed then others. Variations in impurity concentrations result from changes in solution purification and/or feed to the
M. Moats and T. Hymer
will enable a person to make changes to the process. The operational changes will
polarize or depolarize the reactions, which in turn will impact the deposit morphology
and structure.
Eventually, an operator will come to understand not only the effects of process
chemistry and current density, but also the type and frequency of maintenance that
will help produce quality deposits that are easy to strip and produce higher in CE.
These will ultimately improve the operation’s productivity.
These correlations and internalization of lessons learned from “reading the metal” do not happen overnight. It requires time and dedication. The hope is that the
following information will inspire operators and engineers to travel a path to gain
insight and enable them to apply science to real life situations in a cellhouse and
know what to do to improve their bottom line.
Cellhouse Parameters
Within a cellhouse are a variety of different parameters that impact the plating process. Some are readily changeable and others are not. A zinc cellhouse typically has
a variety of flow rates that can be changed, temperature control, copper bus bars carrying current that can be changed, Zn and acid concentrations, cell voltage, cathodes,
anodes, and additives that are can be added to the system. In addition, the electrolyte
will carry impurities from the leaching process that were not fully removed in purification. All of these items can have an impact on the performance of the cellhouse. A
good practice is to collect all this information daily to see how the process changes
and begin to determine the root causes of deposit structure changes and their impact
on performance. A cellhouse is typically designed to have basic operating parameters
and certain process design that may or may not be changed by the operator. However,
even the parameters that are not readily changeable by an operator can be altered due
to improper maintenance or equipment failure and therefore impact other parameters
and change the conditions to make a proper deposit. Studying and understanding the
intercorrelations between all these items will enable informed decisions on changes
in the cellhouse.
Parameters Impacting Polarization
There are certain parameters that are within the control of the operator to increase or
decrease polarization which can be changed to improve the structure of the deposit.
The main parameters are shown in Fig. 4d. There are two groups—those that increasing their value will polarize and those that depolarize the cathode potential. These
parameters can be considered as “levers” that can shift the potential of the cathode.
Some of these parameters are more readily changed then others. Variations in impurity concentrations result from changes in solution purification and/or feed to the