In this final thesis main topic is nitration as termo-chemical process by witch the surface layer of steel or cast iron is enriched with nitrogen through diffusion. This heat treatment results in a high wear resistance, anti-corrosiveness, resistance to elevated temperatures, increased fatigue strenght, high surface hardness along with variety of other benefits. The process that will be discussed in this paper is the process of nitration in the ionized gas, called ion nitriding. In this thesis the main focus is on some personal observations that are the result of 15 years of work on the process of ion nitriding.