Cells with Low Anode Polarization

Cells with a small cathode and a large anode are often used in electroplating technology. In this case, a homogeneous distribution of the deposit over the entire cathode is required. 

Stationary Wire Eiectrode on the Current Density in the Middle of the Eiectrode 

It can be seen from Fig. 3.11 that the dissipation of current lines from the tip of a stationary wire electrode is more pronounced than in the case of the edges of plane parallel electrodes. This is because the dissipation in the former case occurs through the space, while in the latter case, it takes place in one plane, normal to the electrodes, to which two synunetrically positioned points belong. Hence, it can be taken that the overall resistance between the tip of the cathode and anode will be equal to an infinitely large number of resistances, as in the case of the edges of two plane parallel electrodes coimected in parallel, being equal to zero. 

The cell voltage, U, for the part of the system where the current density is homogeneously distributed is given by 

In this way, the ohmic potential drop in a homogeneous field transforms into the electrochemical overpotential for points at the tip of a wire electrode or in some similar position. This means that a tip current density is larger than a current density in a homogeneous field. Finally, if the anode surface area is much larger than that of the cathode, i.e., if 

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