Abstract: The 2Cr13 stainless steel was treated by active screen plasma source nitriding. The effect of the distance between the 2Cr13 stainless steel specimens and the metal screen on the phase structure and properties of the nitrided layer was studied, and it was compared with the traditional direct current plasma nitriding. The results show that a uniform and compact nitrided layer is formed on the surface of the 2Cr13 stainless steel when using both two kinds of nitriding processes. The thickness of the compound layer of the active screen plasma source nitrided specimen is lower than that of the direct current plasma nitrided specimen. As the distance between the nitrided specimen and the metal screen increases from 50 mm, 100 mm to 200 mm, the thickness of the nitrided layer decreases from 18 mm, 15 mm to 6 mm, respectively. The nitrided layer has the same phases structure for speicmens 50 mm and 100 mm away from the metal screen, mainly consist of ε-Fe_2-3N、γ′-Fe₄N and α_N phases, while the nitrided layer which 200 mm away from the metal screen is composed of α-Fe and ε-Fe_2-3N phases. The surface hardness of the nitrided layer treated by two processes reaches 1305-1442 HV0.2, which is 3-4 times of the matrix hardness. The tribological properties and electrochemical corrosion behavior of the active screen plasma source nitrided layer are superior to those of the direct current plasma nitrided layer, with a friction coefficient maintained between 0.62-0.70 and a self corrosion potential between －0.11-－0.18 V.

Key words: active screen plasma source nitriding, 2Cr13 stainless steel, phase structure, wear resistance, corrosion resistance