Electrochemical machining of cemented carbides

The present work is focused on the electrochemical behavior of tungsten carbide cobalt in alkaline ammonia electrolytes under near-ECM conditions. Potentio dynamic measurements were carried out in an electrolyte mixture of sodium nitrate and ammonia. It could be shown that a homogenous dissolution of both phases, the hard phase tungsten carbide and the binder phase cobalt, is possible with this electrolyte mixture. Additionally, galvanostatic pulse experiments coupled with polarographic analysis of the waste electrolyte were carried out to investigate the current efficiency of the machining process. Current efficiencies between 70 and 100% can be achieved under the chosen conditions dependent on the current density.