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Wälzbeständigkeit von ta‐C und a‐C Dünnschichten bis zu 3.000 MPa maximaler Hertzscher Kontaktpressung
Author(s) -
Woydt M.,
Scholz C.,
Manier C.A.,
Brückner A.,
Weihnacht V.
Publication year - 2012
Publication title -
materialwissenschaft und werkstofftechnik
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.285
H-Index - 38
eISSN - 1521-4052
pISSN - 0933-5137
DOI - 10.1002/mawe.201200956
Subject(s) - coating , materials science , composite material , slip (aerodynamics) , contact mechanics , amorphous solid , thin film , metallurgy , nanotechnology , thermodynamics , crystallography , finite element method , chemistry , physics
The slip‐rolling resistances of hard and stiff thin films under high Hertzian contact pressures can be improved by optimizing the “coating/substrate systems”. It is known from former investigations that the so‐called “egg‐shell” effect is no general hindrance for high slip‐rolling resistance of thin hard coatings. The coating stability depends more on specific deposition process and coating/substrate interface design. In this article it is experimentally shown, that pure amorphous carbon thin films with hardness between 15 and 63 GPa can be slip‐rolling resistant several million load cycles under a maximum Hertzian contact pressures of up to 3.0 GPa. Whereas all coatings were stable up to 10 million load cycles in paraffin oil at room temperature, reduced coating lifetime was found in SAE 0W‐30 engine oil at 120°C. It was shown how the coating hardness and the initial coating surface roughness influence the running‐in process and coating lifetime. No clear correlation between coating hardness and coating lifetime could be observed, but friction coefficients seem to be reduced with higher coating hardness. Very low friction down to ˜0.03 in unmodified engine oils was found for the hardest ta‐C film.