presents the wear volume curves as a function of
sliding distance. The wear behavior of the niobium carbide
layers on AISI H13 and M2 steels is compared with
uncoated and ionitrided AISI H13. In all cases, the wear
volume increased when the sliding distance increased. The
wear resistances of the niobium carbide layers on both
steels presented similar behavior and were considerably
more wear resistant than uncoated AISI H13. In comparison
with the ionitrided AISI H13, the NbC layers also
presented higher wear resistances, evidencing that the TRD
treatment was very efficient in the production of wear
resistant coatings. Wear craters imposed on uncoated AISI
H13 and NbC layers for a sliding distance of 177 m are
shown in Fig. 5. In the case of NbC coated H13 steel (Fig.
5b), the wear crater for a sliding distance of 118 m is also
presented. It is clearly observed that NbC coated samples
are considerably more wear resistant than uncoated AISI
H13 steel. The high wear resistance of carbide layers
produced by the TRD process is known [1]. Diebel et al.
[13] showed that VC coating presented wear resistance
higher than TiCN and TiN under Pin-on-disc wear tests. It