Functionality Investigations of Dry-Lubricated Molybdenum Trioxide Cylindrical Roller Thrust Bearings

authored by

Dennis Konopka, Florian Pape, Norman Heimes, Bernd-Arno Behrens, Kai Möhwald, Gerhard Poll

Abstract

In addition to using conventional lubricants, such as oil and grease, rolling bearings can also be used with a dry lubricant. For example, the use of dry lubricant systems is necessary when the application of oils or greases is not possible (e.g., at high temperatures or in aerospace applications). The requirements of a solid lubricant are to reduce friction and wear of mechanical contact partners. In this work, a molybdenum-based coating system was applied by means of physical vapor deposition (PVD). The coating system consists of a molybdenum (Mo) reservoir with molybdenum trioxide (MoO

₃) as the top layer. The MoO

₃, which is particularly important for the run-in and the lubricating effect, is intended to continuously regenerate from the reservoir via tribo-oxidation. To determine the friction and wear behavior, cylindrical roller thrust bearings were used. Experiments demonstrated that the lubrication system is effective and that the frictional behavior has been improved. On the one hand, the frictional torque of the rolling bearings has been considerably reduced and, on the other, significantly extended operating times have been determined compared to unlubricated reference experiments. Simultaneously, material analyses have been carried out by means of scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDX). The investigations showed that the MoO

₃ was transferred to uncoated bearing components. This improved the tribological behavior and reduced abrasive and adhesive wear.

Organisation(s)

Institute of Machine Elements and Engineering Design
Institute of Metal Forming and Metal Forming Machines
Institute of Materials Science

Type

Article

Journal

COATINGS

Volume

ISSN

2079-6412

Publication date

26.04.2022

Publication status

Published

Peer reviewed

Yes

ASJC Scopus subject areas

Materials Chemistry, Surfaces, Coatings and Films, Surfaces and Interfaces

Electronic version(s)

https://doi.org/10.3390/coatings12050591 (Access: Open)

Details in the research portal "Research@Leibniz University"

BibTeX

@article{728606eaf89c40a58184c0ef8f6afaad,
title = "Functionality Investigations of Dry-Lubricated Molybdenum Trioxide Cylindrical Roller Thrust Bearings",
abstract = "In addition to using conventional lubricants, such as oil and grease, rolling bearings can also be used with a dry lubricant. For example, the use of dry lubricant systems is necessary when the application of oils or greases is not possible (e.g., at high temperatures or in aerospace applications). The requirements of a solid lubricant are to reduce friction and wear of mechanical contact partners. In this work, a molybdenum-based coating system was applied by means of physical vapor deposition (PVD). The coating system consists of a molybdenum (Mo) reservoir with molybdenum trioxide (MoO 3) as the top layer. The MoO 3, which is particularly important for the run-in and the lubricating effect, is intended to continuously regenerate from the reservoir via tribo-oxidation. To determine the friction and wear behavior, cylindrical roller thrust bearings were used. Experiments demonstrated that the lubrication system is effective and that the frictional behavior has been improved. On the one hand, the frictional torque of the rolling bearings has been considerably reduced and, on the other, significantly extended operating times have been determined compared to unlubricated reference experiments. Simultaneously, material analyses have been carried out by means of scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDX). The investigations showed that the MoO 3 was transferred to uncoated bearing components. This improved the tribological behavior and reduced abrasive and adhesive wear. ",
keywords = "dry lubricant, friction, Mo-coating, PVD, rolling bearing, wear",
author = "Dennis Konopka and Florian Pape and Norman Heimes and Bernd-Arno Behrens and Kai M{\"o}hwald and Gerhard Poll",
note = "Funding information: Acknowledgments: The results presented in this paper were obtained within the scope of the priority program “Fluidless Lubrication Systems with high Mechanical Load” (SPP 2074) in project 2, funded by the German Research Foundation (Deutsche Forschungsgemeinschaft, DFG)). Grant number 407673224. The authors gratefully acknowledge the German Research Foundation for their financial support of this project.",
year = "2022",
month = apr,
day = "26",
doi = "10.3390/coatings12050591",
language = "English",
volume = "12",
journal = "COATINGS",
issn = "2079-6412",
publisher = "MDPI AG",
number = "5",
}