Phase Composition and Properties of Unalloyed Steels' Surfaces Modified by Intense Plasma Pulses with Various Reactive Gas Fluencies

Unalloyed steels were subjected to the transient treatment using high intensity argon and nitrogen plasma pulses, which melt the near surface layer of steel. In the former case, the pulses induce only heat effects whereas in the latter, the nitrogen atoms generate the formation of nitrogen‐expanded austenite phases. CEMS, GXRD measurements and tribological tests were used to examine the modified samples. It appears that the formation of austenitic phases, including nitrogen‐expanded austenite saturates above some concentration of the retained nitrogen. An improvement of the wear resistance with increase of nitrogen concentration was observed.