Surface and Coatings Technology; 237 (2013) 299-304

In this work, homogeneous as well as gradient a-C:H:W coatings were deposited on a steel substrate. The mechanical properties of both coating systems were determined using nanoindentation. In addition, a multiaxial, 3-dimensional nanoindentation test (reciprocating wear test with nanometre resolution) was carried out in order to analyse the wear-performance of the two different coating systems. By comparing the wear-performance of the gradient coating system to the non-graduated one we were able to show that according to a theoretical approach proposed a few years ago the gradient coating systems lead to a better performance in micro-wear tests as well as in macro-scale wear tests. In addition, a new wear model taking into account the changing stress fields during the wear tests is proposed in order to simulate the wear behaviour of both coating systems.