Gas phase lubrication study with an organic friction modifier

Friction modifier additives play a crucial role in controlling friction and wear of lubricated tribological systems. Model experiments in a controllable atmosphere performed by integrating a tribometer into a system of in situ surface analytical methods in vacuum can give insights into the additives functionality. In this work, thin, well-defined layers of an organic friction modifier (OFM) are adsorbed onto an iron oxide surface by means of an effusion cell immediately before measuring friction and wear. The results show that contrary to the assumption that homogeneous layers are formed, this OFM accumulates in droplets on the surface. Droplet number and radius increase with evaporation time. In friction tests, the smallest friction values are found for a low coverage of droplets. For larger droplets, friction increases due to a capillary neck of additive that forms between the sliding surfaces and is dragged along during the friction test

In-situ studies of the competitive adsorption of lubricant additives

It is known that different types of surface-affine additives (i.e. antiwear/anti-corrosion/ anti-friction) can have very different adsorption behaviour on surfaces (e.g. [1–3]). The interactions can be synergistic or antagonistic in character and influences the near-surface chemistry of the sliding surfaces and therefore also the tribological performance of the system. For wear protection additives, it is for instance known that phosphor and sulfur containing layers are formed under tribological conditions (e.g. [4,5]). In this presentation we will give an overview on an ongoing study of the adsorption of selected additives using novel in-situ approaches. The found correlations are also compared to tribological experiments in order to answer the question whether synergistic effects in adsorption also lead to synergistic effects in wear reduction

Raw Data: Gas phase lubrication study with an organic friction modifier

XPS / tribometer / mass spectrometer raw data supporting the publication "Gas phase lubrication study with an organic friction modifier

Reaction of Dianion from Benzil-4,4'-dimethyldianil with Molybdenum Hexacarbonyl Leading to a Dianilinostilbene Complex

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