almost independent of the substrate [1], not being influenced
by the existing alloying elements of the steels. The
hardnesses of the layers on AISI H13 and AISI M2 steels
were 2333.3T56.4 and 2344.9 T69.6 HV0.050, respectively.
These levels of hardness are expected for NbC layers
obtained by TRD treatments [5].