Micro- and nanotribological characterization of molybdenum oxide based coatings on 100CR6 bearing steel surfaces

verfasst von

Dennis Konopka, Florian Pape, Norman Heimes, Tim Matthias, Simon Schöler, Kai Möhwald, Bernd-Arno Behrens, Gerhard Poll

Abstract

Dry lubricated bearings are used in applications that are exposed to high temperatures or other ambient conditions that prohibit the use of lubricants. Examples can be found in the chemical or food industries. To handle such conditions, a molybdenum based layer system was developed for the dry lubrication of rolling contacts. The molybdenum oxide layers are generated by Physical Vapor Deposition (PVD). By using a magnetron sputter cathode, it is possible to produce a PVD molybdenum oxide multiple layer system. In the pre-investigation phase, various parameters (power, sputtering time, oxygen mass flow, etc.) were used for the preparation in order to achieve optimum adhesion and material strength. In the current project phase, the coatings were qualified by applying microtribological methods. In a first step of qualification, the nano hardness and Young's modulus were investigated via nanoindentation. Additional nano scratch tests allow conclusions regarding the friction and elastic properties of the coatings. In the second step of qualification, the coatings were qualified by micro wear and scratch tests by applying a milli-tribometer. The setup allows the measurement of the frictional properties of a 100Cr6 (AISI 52100) ball against a coated counterpart under oscillating motion. Scratch tests were performed by applying a Rockwell diamond tip with a radius of 5 μm with forces of up to 1 N and scratch lengths of up to 20 mm. The properties of the coatings regarding the transition from nano to micro scale are observed and taken into account for the layer development. With these results it is possible to characterize the generated layers and to define the wear and the optimal parameters for the PVD process. After qualification the coatings will be applied to radial bearing surfaces. The intended use of dry lubricant coating systems on rolling bearings will be presented.

Organisationseinheit(en)

Institut für Maschinenkonstruktion und Tribologie
Institut für Umformtechnik und Umformmaschinen
Institut für Werkstoffkunde

Typ

Aufsatz in Konferenzband

Seiten

308-315

Anzahl der Seiten

8

Publikationsdatum

2019

Publikationsstatus

Veröffentlicht

Peer-reviewed

Ja

ASJC Scopus Sachgebiete

Allgemeine Materialwissenschaften

Elektronische Version(en)

https://doi.org/10.15544/balttrib.2019.49 (Zugang: Geschlossen)