Verschleißschutz und Korrosionsbeständigkeit von austenitischem Stahl durch Plasmadiffusionsbehandlung

In this paper, we report on a series of experiments designed to study the influence of plasma nitriding on the mechanical properties and the corrosion resistance of austenitic stainless steel, Plasma nitriding experiments were conducted on AISI 304L steel in a temperature range of 375-475 °C using pulsed-DC plasma with different N2-H2gas mixtures and treatment times. First of all, the formation and the microstructure of the modified layer will be highlighted followed by the results of hardness measurement, adhesion testing, wear resistance and fatigue life tests. In additon the corrosion resistance of the modfied layer is desribed. The microhardness after plasma nitriding is increased by a factor of five compared to the untreated material. The adhesion is examined by Rockwell indentation and scratch test. No delamination of the treated layer could be observed. The wear rate after plasma nitriding ist significantly reduced compared to the untreated material. Plasma nitriding produces compressive stress within the modified layer. This treatment improves the fatigue life which can be raised by a factor of ten at a low stress level. The results show that plasma nitriding of austenitic stainless steel is a suitable process for improving the mechanical and the technological properties without significantly effecting the excellent corrosion resistance of this material.