In this study, Electrochemical Machining (ECM) phenomena of sintered carbide are investigated. One of the biggest problems in ECM of sintered carbide is the elution of cobalt, which is the binder of the material. When too much cobalt is eluded, the strength of the material is deteriorated and it cannot be used as a die, particularly in cold forging. In this report, the prevention technology of Co elution is discussed. First, the authors have conducted a simple experiment with a beaker and the results indicated the possibility of inhibiting cobalt elution by adding Co ion into the electrolyte. Then, a machining experiment was carried out with electrolyte flushing, and it was shown that sintered carbide can be machined without excessive Co elution.

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