Diamond-like carbon (DLC) coatings consist of a disordered mixture of sp3 as well as sp2 networks. These thin, metastable-amorphous carbon (a-C) layers possess a high hardness combined with low tribological properties and excellent wear resistance as compared to other coatings, i.e, CrN or TiN. Based on the latter properties, these coatings can be employed wood machining and forming tool coatings. However, the a-C films require a multi-layer deposition due to their inferior adhesion onto the steel substrate based on the chemical bonding as well as intrinsic stresses. Thus, the deposition of interlayers is required to improve the coating adhesion and, consequently, the fatigue performance. In addition, components featuring DLC-coated thin films are exposed to high cyclic stresses which require thorough investigations regarding the fatigue properties of the thin, fabricate multi-layers.
In order to shed light on the fatigue performance of the generated DLC multi-layer coatings via magnetron sputtering, cyclic three-point bending tests (R=0.1) have been conducted in a quasi in-situ manner. The first failure of the multi-layer system, i.e., a delamination or a crack, is detected via an acoustic emission unit. Finally, the presentation at the Materials Science Engineering will elucidate the fatigue characteristics and the microstructural properties obtained for DLC multi-layer coatings.