A study on the active species and the nitride layer formation behavior by means of optical emission spectroscopy during the plasma nitriding of steels

摘要

In order to characterize the behavior of activespecies during the pulse plasma nitriding process, OES(opticalemission spectroscopy) measurements were performed for variousgas compositions, treatment temperatures, duty factors ratios anddifferent gas pressures in the reactor. Results of the OESmeasurements were compared to those of the metallurgicalanalysis of plasma nitrided sintered steel and high speed steelsubstrates. It was found that the spectral intensities of N_2+ andN_2 were influenced by treatment parameters and the thickness ofnitride layer and size of micro-pore increased with increasing thetemperature and pulse ratio. Especially, the compound layer wasmainly influenced by gas pressure.