The nitriding performance of low power electron beam excited plasma was investigated by characterizing the compound layer formed on the surface of nitrided low alloy Cr-Mo steel specimens. In an attempt to maximize the dissociation of N2
, the acceleration voltages applied in our experiments were set within a range that corresponds to the maximum dissociation cross section of N2
. In this experiment, particular attention was given to the effect of the treatment time on the surface morphology, composition, and Vickers hardness of the treated specimen. The results show that the peak intensity of the alpha Fe observed for the untreated specimen decreased as the treatment time increased. Moreover, the peak intensities depicting the formation of the nitride compound layers, Fe4
N and Fe3
N phases, increased with the treatment time. Consequently, the surface hardness of the treated low alloy steel specimen was increased to 1010HV and a nitrided depth of up to 120μm was attained in 4.5 hours of treatment time.