can be observed in this work that NbC coatings also
demonstrate high wear resistance, by using a new wear
resistance test.
Worn surfaces of the NbC coated H13 and M2 samples
are shown in Fig. 6. Although the tests have been
accomplished under dry sliding condition, the wear mode
observed was abrasive wear, with a presence of parallel
scratch marks, and of a smooth (polished) surface with no
evident directionality. The wear debris from the layers is
responsible for the grooving as a result of high hardness of
the niobium carbide (¨2300HV). The smooth wear surface
was probably formed by activity of the small niobium
carbide particles rolling in the contact region between the
ball and the sample. According to Adachi and Hutchings
[10], parallel grooves (known as grooving wear or two-body