XC38 carbon steel was nitrided in a low-pressure R.F. plasma using a mixture of 60% N-2-40% H-2 without cathodic bias on the samples. The experiments were carried out at different temperatures for various time durations. The generated nitride layers were characterized by SEM observations, XRD and GDOS analyses. These analyses indicate that the compound layer was composed of the gamma'-Fe4N phase with a surface content of N close to 6 wt%. An approach was used to study the growth kinetics of the compound layer at 500 degrees C. Furthermore, it was concluded that its kinetics follows a power law, which deviates from the classical parabolic growth. (c) 2007 Elsevier B.V. All rights reserved.