Nitriding of an H13 die steel in a dual plasma reactor

The performance of a dual plasma reactor in nitriding a H13 steel was investigated and compared to other nitriding methods applied to this material. The aim was to explore the advantages of combining a weakly ionized plasma unit and a postdischarge plasma reactor to process this material. Samples of H13 were nitrided at 500, 550, and 600 degreesC for times ranging between 5 to 10 h. The hardness distributions obtained revealed a substantial advantage of the present method over conventional gas nitriding and some improvement over other plasma-assisted methods, especially in the development of smooth profiles. This was attributed mainly to enhanced diffusion provided by the postdischarge flow. The evolution of hardness as a function of time and temperature displayed an aging type of behavior that was related to the formation and growth of CrN as the hardening phase.