In Situ Studies on the Competitive Adsorption of Lubricant Additives

A key factor for improvement and innovation in lubricant development is a fundamental understanding of adsorption processes and competing adsorption mechanisms [1]. Many different base oils and additives, as well as various surfaces build a complex interaction space, which has been difficult to map with in-situ methods so far.

Here we present a study on the adsorption of corrosion inhibitors, anti-wear additives and friction modifiers from a synthetic and a mineral base oil on metal (Fe2O3) surfaces. In order to obtain quantitative and spatial data during the adsorption process we set up a combined quartz crystal microbalance (QCM-D) and confocal scanning laser microscope (CLSM) [2]. In addition to QCM-D and CLSM, also a UHV-tribometer was used to study the performance of gas phase deposited additives films without environmental interferences. In combination with macroscopic performance tests using a “ball-on-three-plates-tribometer” and corrosion tests, the adsorption, the morphology and the mechanical properties of the additives were correlated with their performance.
The multidisciplinary results provide exciting new insights into lubrication fundamentals and reveal so far undescribed phenomes and mechanisms of action. ... mehr

[1] J. Guegan et al. ,Friction Modifier Additives, Synergies and Antagonisms, Tribology Letters 67 (2019)
[2] J. Honselmann et al., submitted, 2019