Nitrogen-ion implantation can be used to improve the wear and corrosion behaviour of moulds for plastic injection by modifying the nearsurface layers of these materials. In this study, an FeCr ferritic stainless steel (X36CrMo17, similar to AISI-420F) was ion implanted with 85 keV nitrogen ions to low and high doses of 2Â10 17 and 1Â10 18 ions/cm 2 at a substrate temperature b200 8C in an industrial implantation facility. The N-implanted layer microstructures, thicknesses, and hardnesses were studied by a combination of symmetric and grazing incidence X-ray diffraction (XRD and GIXRD), conversion electron Mfssbauer spectroscopy (CEMS), cross-sectional scanning electron microscopy (SEM), and nanohardness measurements. The friction, wear, and corrosion behaviour were investigated by a pin-on-disc tribo tester and a salt spray corrosion analysis method. The XRD, CEMS, and SEM analyses indicate that the N-implanted layers are~0.05-0.08 Am thick and are composed of q-(Fe,Cr,Mn) 2+x N with paramagnetic and magnetic characteristics. The treated layer shows nearly two times better corrosion resistance than does the substrate. The wear and nanohardness measurements indicate that the wear behaviour and the Nimplanted layer hardness are dose dependent and the latter is increased by more than a factor of 1.6 for the high-dose implanted specimen in comparison with that of the substrate material. D

Plasma nitriding can be used to improve wear and corrosion behaviour of moulds for plastic injection by modifying the near-surface layers of these materials. In this study, a ferritic stainless steel (X36CrMo17) was plasma nitrided at 520-540 8C for 15-18 h under various gas mixtures of N 2 +H 2 in an industrial nitriding facility. The nitrided layer microstructures, thicknesses, and strengths were studied by X-ray diffraction (XRD), conversion electron and X-ray Mfssbauer spectroscopies (CEMS and CXMS), cross-sectional scanning electron microscopy (SEM), and cross-sectional nanohardness measurements. The corrosion behaviour was investigated by a salt spray method. Combined Mfssbauer, XRD, and SEM analyses demonstrate that (Fe,Cr,Mn)-nitrides, the q-and gV -nitrides, the Fe 3 C-like carbide, and CrN are distributed in the top nitrided layers of several micron thickness. The CEMS and CXMS analyses clearly show the nearly complete decomposition of the surface and deeper layers into phase separated mixtures of pure bcc-Fe, (Fe,Cr,Mn)-nitrides, and CrN. The nitriding conditions with the gas composition N 2 /H 2 =1 produces the thickest nitrided layer (~135 Am) with enhanced corrosion protection. The nanohardness of the surface layers is found to be plateau-shaped and increased by about a factor of three in comparison to that of the substrate material. D