Effects of the process parameters on the layer formation behavior of plasma nitrided steels

In order to investigate the behavior of nitrogen active species during the pulsed d.c, plasma nitriding process, emission spectra measurements by usin g optical emission spectroscopy (OES) were performed for various treatment temperatures, duty factors and different gas pressures in the reactor. Resu lts of the OES were compared to those of the metallurgical analysis of plas ma nitrided sintered steel and high speed steel substrates. The spectral in tensities of N-2(+) and N-2 were influenced by process parameters (gas pres sure, treatment temperature and duty factor). The thickness of the nitride layer and the size of micro-pore increased with increasing treatment temper ature. Especially, the thickness of the: compound layer was mainly influenc ed by the gas pressure in the reactor. (C) 2001 Elsevier Science B.V. All r ights reserved.