Abstract Plate anode and specimen as cathode parallels with each other, and both are sealed with agents in stainless box. The influence of direct current field (DCF) on nitrocarburizing has been investigated by applying DCF between the anode and the specimen as cathode during the soaking. The test results indicate that DCF can enhance nitrocarburizing, modifies hardness profile along the case depth and save energy. DCF has the heating effect to agents and specimen, which enhances chemical reactions in the agent, accelerates the diffusion of nitrogen and carbon atoms in the specimen. It is proposed that DCF make the concentrations of nitrogen and carbon at and around the specimen as cathode much higher than in any other position compared with the conventional powder-pack nitrocarburizing (CPN) process by forcing nitrogen-/carbon-containing species diffuse toward the cathode, which relatively decreases nitrogen/carbon absorption by inner wall surface of the pack box and the non-working surface of the specimen. DCF’s physical effect of enhancing chemical reaction in the agent increases the activity and productivity of nitrogen-/carbon-containing species, which overcomes the shortcoming that CPN can not produce enough boron-containing species by conventional way of heating.
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