Some Testing Cells for the Study of Electroplating Devices

The complete theoretical treatment is given for two kinds of cells, both of which are shown to yield a reasonably linear primary current density distribution along the cathode, calculated under the assumption of negligible polarization. The actual value of these current densities can be ascertained directly from the total current fed into the cell. The first cell is very similar to that proposed by Hull, i.e., trapezoidal in shape, the angle of the slanting side being 45°. The electrodes can be placed either along the parallel sides of the cell or, as first suggested by Hull, along the other two sides, when a singularity of the current density appears on the slanting electrode. In both cases the current density may be arranged to be very nearly linear over almost two thirds of the length of the cathode. The second cell is triangular in shape; the cathode is placed along the base of a 45° isosceles triangle whereas the anode occupies a part of one of the other sides. The current density distribution along the cathode has almost a triangular shape with good linearity. Both cells are easy to construct and normalized graphs of the current density allow for straightforward comparison with experimental results.