respectively. In addition, for depths on the order of 55 μm, hardness
profiles show tempered substrate bulk hardness of about 375 HV0.01
for all studied conditions. It is important to emphasize this result,
since it indicates the diffusion characteristic of the process. Note
that both the depth and hardness obtained for the profiles are very
similar, despite the different CH4 contents, being in accordance with
the same carburizing temperature and time utilized in the treatments.
Finally, the importance of the CH4 content present in the gas
mixture as treatment parameter was strongly evidenced by the
higher hardness and thicker outer layers obtained in treated surfaces,
as previously discussed.