To modify the surface structure of AISI 1005 steel and its properties without any dimensional loss, different plasma surface treatments were performed at low temperatures (500 °C) in this study. The samples were subjected to single plasma treatments including: nitriding (N5% and N3%), carburizing (CE) and ferritic nitrocarburizing (NC) and to duplex treatments of nitriding followed by carburizing (N5%+CE and N3%+CE) and ferritic nitrocarburizing followed by carburizing (NC+CE). The gas mixture used for these treatments was varied as follows: nitriding (5%N 2 +95%H 2 and 3%N 2 +97%H 2 ), carburizing (5%CH 4 +95%H 2 ) and ferritic nitrocarburizing (5%N 2 +1.5%CH 4 +93.5%H 2 ). A microstructural characterization of the samples was carried out using optical and scanning electron microscopy in addition to XRD analysis. Microhardness testing was also performed. The XRD analysis showed a stabilization of the outermost cementite layer for all of the carburizing treatments. The results show that a greater hardness increase was achieved for the nitriding treatment as well as a more regular compound layer. However, a greater depth of hardening was obtained in samples with NC+CE and N5%+CE, which extended to the hardened depth to 800 μm.

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