P. M. Reinders, P. Kaestner, G. Bräuer, Technical University Braunschweig, Braunschweig, Germany
Austenitic steels are known for their high corrosion resistance but at the same time possess low wear resistance. Plasma nitriding improves the tribological properties but can also influence the corrosion behavior.
Aim of this study is to develop a model that allows to predict the thickness of the s-phase and the change of corrosion behavior in plasma nitriding processes for austenitic stainless steels. For this purpose, a number of processes were executed under specific variation of temperature ranging from 360 °C to 450 °C and duration of 10 to 24 h. Other process parameters such as voltage or gas mixture remained constant. A temperature dependent gradient was determined and with it, it is possible to predict the thickness of the s-phase for any given treatment temperature and process duration in the given temperature window. Additionally, it is possible to choose one of the mentioned process parameters and to combine it with the second one via iso-thickness curves in order to obtain the desired thickness of the s-phase. The model also includes the change of corrosion behavior depending on these.
The developed model was verified by control experiments and shows a maximum relative error of 5.5 %.