Interactions Between Anti-Wear Additives and Corrosion Inhibitors in Oil-Lubricated Rolling Contacts

Rolling bearings are lubricated with oil or grease to reduce wear. In addition to the base oil, these lubricants contain various additives to ensure high performance. Interactions can occur between the additives, leading to synergistic effects—whereby the performance of the individual additives reinforces each other—or to antagonistic effects, whereby the functionality of one additive is impaired by another. Nearly 50 % of rolling bearings fail due to abrasive/adhesive wear and moisture corrosion. This underscores the need for effective EP/AW additives and corrosion inhibitors (CI). Since both types of additives compete for the metal surface, antagonistic effects are to be expected. A thorough understanding of the interactions between EP/AW additives and CIs is crucial for avoiding undesirable antagonisms and leveraging synergies to reduce additive dosages.

In the preceding project (IGF 01IF22309N), initial effects of the additive combination, concentration, and contact conditions on the performance of EP/AW when CI was added were demonstrated. The DGMK 902 research project builds on these results and systematically investigates the influence of CI on the wear protection of oil-lubricated rolling bearings, as well as its effects on tribocorrosion protection. The goal of the project is to fully exploit the potential of the additives by understanding the interactions between EP/AW and CI in oil-lubricated rolling contact. SMEs can benefit from the results in a variety of ways. Lubricant developers will be provided with a methodology for identifying suitable combinations of additives. Lubricant users can make more targeted preliminary selections of additives and avoid unsuitable combinations, thereby reducing testing requirements. The potential of the additive formulation is maximized, allowing for more economical use.

This project is funded by the Federal Ministry for Economic Affairs and Energy pursuant to a resolution of the German Bundestag (IGF Project 01IF25501N).

The grant award letter from the BMWE has been received, and the project will begin on October 1, 2026.