New Study on Self-Regenerative Mo-Based Solid Lubricant Coatings via APS

In collaboration with the Institute of Materials Science (IW), the Institute of Machine Design and Tribology (IMKT) has published a new article in Tribology Transactions.

The publication, entitled “Self-Regenerative Mo-Based Solid Lubricant Coatings Deposited by APS as a PVD Alternative: Mechanical and Tribological Performance”, is authored by Dennis Konopka, Ricardo Crespo Martins, Mareike Dukat, Florian Pape, Kai Möhwald, Gerhard Poll, and Max Marian.

Solid lubricants are crucial when liquid lubricants cannot be applied. While PVD coatings can release MoO₃ through tribo-oxidation to form a self-regenerating film, their thickness is limited to only a few micrometers, restricting the lubricant reservoir.

This study explores whether Atmospheric Plasma Spraying (APS) can be used to deposit significantly thicker reservoir layers with regenerative properties on bearing steel. Mechanical, tribological, and structural properties were analyzed using microindentation, ball-on-plate tribometer tests under dry-running conditions, optical and laser-based surface analysis, SEM, and EDX.

The results show that, despite its lower hardness, the APS coating provided excellent wear protection under various loads and sliding velocities. EDX analysis further revealed that abrasive wear was prevented and a protective tribo-oxidative reaction layer was formed. These findings highlight APS as a promising approach for large-scale machine elements such as rolling bearings.

Link: https://doi.org/10.1080/10402004.2025.2519334