Self-Regenerative Mo-Based Solid Lubricant Coatings Deposited by APS as a PVD Alternative

Mechanical and Tribological Performance

verfasst von

Dennis Konopka, Ricardo Crespo Martins, Mareike Dukat, Florian Pape, Kai Möhwald, Gerhard Poll, Max Marian

Abstract

Solid lubricant coatings are essential for reducing friction and wear in tribo-mechanical systems, particularly in environments where traditional liquid lubricants can’t be used or fail. It has been reported in literature that self-regenerating physical vapor deposition (PVD) coatings can be designed in such a way that they continuously release MoO₃ as a solid lubricant through tribo-oxidation. However, a disadvantage of PVD coatings is the limited layer thickness of just a few micrometers and thus the limited solid lubricant reservoir. In contrast, atmospheric plasma spraying (APS) allows the deposition of thicker reservoir layers, potentially extending service life under tribological stressing. Therefore, the aims of this study are to determine whether APS coatings with regenerative properties can be deposited on bearing steel and to assess their tribological performance. The mechanical, tribological, and structural behavior were analyzed using microindentation, ball-on-plate tribometer testing under dry conditions, optical and laser scanning, scanning electron microscopy (SEM), and energy-dispersive x-ray spectroscopy (EDX). Despite the relatively low hardness of the APS coating, excellent wear resistance protection was demonstrated at various loads and sliding velocities. Additionally, EDX analyses revealed that abrasive wear was prevented and a protective film was formed through tribo-oxidation, effectively shielding the surfaces. The results thus indicate the effectiveness of the APS coating and underline its potential for large-scale machine elements, such as rolling bearings.

Organisationseinheit(en)

Institut für Maschinenkonstruktion und Tribologie
Institut für Werkstoffkunde

Externe Organisation(en)

Pontificia Universidad Católica de Chile

Typ

Artikel

Journal

Tribology transactions

Band

68

Seiten

1036-1051

Anzahl der Seiten

16

ISSN

1040-2004

Publikationsdatum

18.09.2025

Publikationsstatus

Veröffentlicht

Peer-reviewed

Ja

ASJC Scopus Sachgebiete

Werkstoffmechanik, Maschinenbau, Oberflächen und Grenzflächen, Oberflächen, Beschichtungen und Folien

Elektronische Version(en)

https://doi.org/10.1080/10402004.2025.2519334 (Zugang: Offen)