A multi-cathode metal vapor vacuum arc (WEVVA) ion source has been designed. It contains an array of 18 cathodes, any of which can be switched into operation rapidly while under vacuum.

Practice shows that improve the metal electrical crystallization in the cathode polarization effect, can improve the generation of the nucleation rate, easy to get crystallization meticulous coating.

In the simplest case, the anode would be one metal, perhaps iron, the cathode another, say copper, and the electrolyte might or might not have the same composition at both electrodes.