Correlation of nanomechanical and nanotribological behavior of thin DLC coatings on different substrates

The use of tribological coatings with film thicknesses in the submicrometer regime is an increasing field of applications. In this work diamond-like carbon films with a thickness of 250 nm deposited via plasma enhanced chemical vapor deposition on different substrates are characterized by nanoindentation and microscratching in combination with scanning probe microscopy. This configuration allows the testing of samples with loads between 1 μN and 10 mN and a high local resolution. First the influence of the substrate is analyzed with respect to the mechanical properties of the film/substrate system. Furthermore effects of different substrates with respect to the friction and wear behavior for scratch as well as oscillating tests are observed. These results are correlated to the results of nanoindentation. The substrates cover the range of very soft (SU8 photoresist) up to very hard (AlTiC ceramic) materials showing a clear influence on the tribological response of the systems even in case of indenter displacements being small compared to film thickness (e.g. in the low-load regime).