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B. Kohlhauser, H. Riedl, M. Ripoll Rodríguez, C. Gachot, P.H. Mayrhofer:
"In-situ solid lubricant formation on W or Mo based carbide and nitride coatings in lubricated tribo contacts";
Talk: Spring Meeting of the European Materials Research Society 2018, Strasbourg; 2018-06-18 - 2018-06-22.

Increasing political and social pressure on manufactures demonstrates that producing cheap is not enough. Longer lasting as well as environmental friendly products, tools and processes are demanded. One major contributor to achieve these goals are coatings for tools and component surfaces, that are under severe stress. While conventional hard coatings are well established, a new generation of functional coatings is pushing beyond mechanical properties. Some transition metal based coatings aim to combine excellent mechanical properties with an optimization of friction and wear by interacting with lubricants to form low friction tribofilms.
Molybdenum and tungsten based nitride and carbide coatings were prepared by physical vapour deposition and their mechanical, structural, and chemical properties were investigated with nanoindentation, energy dispersive x-ray spectroscopy, X-ray diffraction, and transmission electron microscopy.
The most promising coatings, based on these investigations, were subjected to tribological investigations in lubricated contacts. While an in-situ generation of MoS2 and WS2 between the coatings and a sulphur agent in the oil was already discovered, this work addresses the need for a "green" alternative to conventional sulphur based oil additives. Due to the much lower sulphur contents in "green" additives, the coatings need to be tailored to these "green" additives to allow for the formation of effective lubricating tribofilms.

In-situ formation, transition metal dichalcogenides, wear protection, PVD, magnetron sputtering, tungsten nitride, tungsten carbide, molybdenum carbide