Factors affecting the electroplating deposition rate include:
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Nature of electrolyte: The nature of the electrolyte used in the electroplating process greatly affects the formation of a smooth deposit. A smooth deposit can be provided by employing the electrolyte from which complex ions can be obtained.
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Current density: The rate of electrodeposition depends on the rate at which crystals grow and the rate at which fresh nuclei are formed. Therefore, the deposit of metal will be uniform and fine-grained if the current density is used at a rate higher than at which the nuclei are formed. The deposition will be strong and porous if the rate of nuclei formation is very high due to very high current density.
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Temperature: Sometimes pulse electroplating can be performed in a heated electroplating bath to increase the depositing rate since the rate of most chemical reactions increases exponentially with temperature per the Arrhenius law.
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Conductivity: The rate of metal deposition increases with the increase in current density up to a certain limit after which the electrolyte surrounding the base metal becomes so much depleted of metal ions that the further increase in the current density does not cause an increase in the rate of deposition. The use of current density beyond this limit results in the electrolysis of water and liberation of hydrogen on the cathode.
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Ionic mass transport: Enhanced plating rates can be further increased by providing additional ionic mass transport, over and beyond that produced by local thermal microstirring.
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Density of deposition: The density of the deposition is one of the major factors affecting the electroplating deposition rate. The rate of electrode deposition will entirely depend on the rate at which the crystals of the electrode deposit grow, the current density, and how the nuclei get formed.
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Stirring: Stirring may increase the transfer/diffusion rate of metal ions from bulk solution to the electrode surface. Stirring setting varies for different electroplating processes.
