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

authored by: 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.
Organisation(s): Institute of Machine Elements and Engineering Design
Institute of Metal Forming and Metal Forming Machines
Institute of Materials Science
Type: Conference contribution
Pages: 308-315
No. of pages: 8
Publication date: 2019
Publication status: Published
Peer reviewed: Yes
ASJC Scopus subject areas: General Materials Science
Electronic version(s): https://doi.org/10.15544/balttrib.2019.49 (Access: Closed)
: Details in the research portal "Research@Leibniz University"

BibTeX

@inproceedings{73f651b0945840129393e2640b3515f5,
title = "Micro- and nanotribological characterization of molybdenum oxide based coatings on 100CR6 bearing steel surfaces",
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.",
keywords = "Dry lubrication, Friction, Microtribology, Molybdenum, Molybdenum oxide, Scratch test, Wear",
author = "Dennis Konopka and Florian Pape and Norman Heimes and Tim Matthias and Simon Sch{\"o}ler and Kai M{\"o}hwald and Bernd-Arno Behrens and Gerhard Poll",
note = "Funding Information: A very special thank you goes out to the Deutsche Forschungsgemeinschaft (German Research Foundation, DFG). This project wouldn{\textquoteright}t have been possible without appropriate financial support. The DFG is supporting the research program Fluidless Lubricationsystems with high mechanical Load (SPP 2074, project number 357505886).; 10th International Scientific Conference BALTTRIB 2019 ; Conference date: 14-11-2019 Through 16-11-2019",
year = "2019",
doi = "10.15544/balttrib.2019.49",
language = "English",
pages = "308--315",
booktitle = "Proceedings of 10th International Scientific Conference BALTTRIB 2019",
}