Adhesion of DLC Films

The high compressive stresses in hard a-C H and ta-C films (up to 10 GPa, depending on the deposition conditions, especially the bias voltage) [79] frequently lead to film delamination and thus limit the attainable film thickness. For many years thicknesses of more than 1-2 pm could not be realized on technically relevant substrates like steel, hardmetal or glass. Considerable improvements were achieved by applying intermediate layers consisting of aSi H [80], metals (Al, Ti, Ni) [81, 82], or multilayers (Ti-TiCN-TiC) [83], for example. For the characterization of 

However, the reliable and reproducible preparation of well-adhering a-C H films is commonly not a simple task and requires a good control of several process parameters. Traces of oxygen in the films, to give just one example, can cause a drastic deterioration of the film adhesion. 

On the other hand, there are very reliable industrial processes for deposition of MeC H coatings. MeC H films have lower stresses than a-C H ( 1 GPa) [34, 85] Therefore their tendency to delaminate is considerably reduced. Furthermore, intermediate layers can be prepared very easily using non-reactive sputtering from 

---