Reducing or avoiding friction and wear is still a great challenge e.g. for the automobile industry. The avoidable losses can lead to economic losses up to 5 % of the gross national product of an industrial nation. Fraunhofer IWS carries out researches to minimize these wastes on one hand by coatings and on the other hand by laser structuring of element surfaces.
In this context low-friction tetraedic-amorphous carbon layers (ta-C) were equipped with periodic micro- and nano topographies by Direct Laser Interference Patterning (DLIP). Nano structures with 90 nm width (period: 180 nm) could be produced with one laser pulse.
Tribological analyses of these functional surfaces showed a significant decrease of adhesive forces between the friction partners. Simultaneously the by DLIP produced recesses served as lubricant reservoir. As a result the friction coefficient of already low-frictional ta-C layers was lowered by another 30 %.
Both technologies, coating and DLIP, can be applied to plain, big surfaces as well as to complex elements like bevel wheels. Therefore they offer a broad range of application.