Pure iron and carbon-iron sintered species were plasma nitrocarburized and nitrided at 700 degrees C. A pressure equals to 3 torr and times of 0.25, 1, 2 and 3 hours were used for both species. For the nitrocarburized pure iron species the gaseous mixture consisted of 90%N-2/10%H-2 and CH4 with 1.0, 1.5 and 2.0%. For nitrided samples the gaseous mixture was kept constant at 90%N-2/10%H-2. Nitrocarburized and nitrided layers were examined by standard optical and scanning electron microscopy (SEM), X-ray diffraction and electron probe microanalyser (EMPA). Results have shown microstructural modification of the thickness in the compound layer. Micropore formation was also detected in the austenitic region adjacent to the compound layer.