Plasma Nitriding Process and Best Applications

Plasma nitriding is the low-nitriding potential process characteristic of its ability to nitride stainless steels and powder metal components without special preparations or unusual controls. This is possible thanks to its specific mechanism and presence of sputtering, the phenomenon which is inherently part of the process. The compound zone formed is very important whenever a good bending fatigue property of the part is needed. Mechanical masking, protection from direct contact of the glow discharge with a given surface, avoids hardening of the mechanical components in the areas, which should stay soft, such as the threads and small holes. The uniformity of nitriding large/long parts, such as shafts and extruder screws, allows economical treatment in module-type vessels. Easy doping of the plasma with hydrocarbons allows for forming thicker compound zone of the ε-Fe₂N_xC_y-type. This significantly improves tribological and anticorrosion properties. The plasma process can be carried out also at the temperature range 350-400° C to all types of stainless steels. Formation of expanded austenite at such a low temperature is possible when nitrogen or carbon is diffused. This is applied for stainless steels where their corrosion resistance must be supported or enhanced in their wear resistance applications.